From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2022-50865][MODERATE REGULAR] tcp: fix a signed-integer-overflow bug in tcp_add_backlog() [ Upstream Date: Wed, 16 Sep 2026 13:35:09 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2022-50865 X-AL-KERNEL-Priority: MODERATE REGULAR X-AL-KERNEL-Severity: MODERATE REGULAR X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 4 X-AL-KERNEL-ActionableScore-Lower: 2 X-AL-KERNEL-Commit: 9d04b4d0feee12bce6bfe37f30d8e953d3c30368 List-Id: CVE: CVE-2022-50865 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: tcp: fix a signed-integer-overflow bug in tcp_add_backlog() [ Upstream Commit: 9d04b4d0feee12bce6bfe37f30d8e953d3c30368 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9d04b4d0feee12bce6bfe37f30d8e953d3c30368 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2022-50865 Analysis date: Wed, 16 Sep 2026 13:35:09 -0400 ActionableScore: 4 ActionableScore lower bound: 2 Actionable bucket: Borderline / manual review recommended Manual review required: YES Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2022-50865 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2022-50865 The original announcement does not normally provide a security severity estimate, CVSS assessment, or enough information to determine whether the reported kernel bug represents a practically relevant security issue. This report was generated by AL-KERNEL, an AI-assisted Linux kernel vulnerability analysis system developed by Alexander Larkin. It combines an autonomous classifier with LLM-assisted technical analysis and a separate ActionableScore mechanism. The purpose of this report is to prioritize Linux kernel CVEs before manual review, identify cases that require prompt investigation, and support automatic closure of issues that are unlikely to have meaningful security impact. Published priority for this report: MODERATE REGULAR Manual review required: YES A detailed explanation of the methodology and priority rules is included at the end of this message. ====================================================================== AL-KERNEL CLASSIFICATION RESULT ====================================================================== CVE-2022-50865 MODERATE https://www.kernelcve.org/list/?q=CVE-2022-50865 CHECK WITH IMPACT FROM ORIG NN IMPORTANT Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';CWE-190;CWE-682;**CWE-400;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.9';DESCR 'A signed integer overflow in tcp_add_backlog() can occur when sk_rcvbuf, sk_sndbuf, and a 64 KB headroom are combined while computing the receive backlog limit. A remote peer may be able to trigger the affected TCP receive path only if the target already has a socket configured with extremely large buffer values and packets are queued to the backlog while the socket is owned. For the CVSS the PR:N is used for the paranoid network scenario because the attacker may only need TCP reachability to such a preconfigured target socket, while reliable setup of the vulnerable condition is configuration dependent. The impact is primarily denial of service through a kernel warning, sanitizer failure, crash, or broken TCP backlog handling. No concrete UAF, OOB write, arbitrary write, or information leak primitive is visible from the patch context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 3) MAYBE REMOTE SIMPLEFIX NETWORK CVEOUTDATED PACKET LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=4 ActionableScoreLower=2 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=RECOMMENDED AutoDowngradeAllowed=YES 1. ActionableScore * Raw conservative score: 2 * Conservative score: 2 * Raw paranoid score: 4 * Paranoid score: 4 * Final recommended bucket: **Borderline / manual review recommended**:: No floor or cap was applied. 2. Signal breakdown Conservative signals: * +1 Common networking core path / packet-processing path: tcp_add_backlog() is in the TCP receive/backlog path. * +1 Availability impact realistic: signed integer overflow can produce an incorrect backlog limit and may cause TCP receive/backlog failure, packet drops, warning, or sanitizer-triggered failure in affected configurations. Paranoid signals: * +1 Common networking core path / packet-processing path: same TCP receive/backlog path. * +2 Conditional remote reachability: once a target socket is already configured with sufficiently large sk_rcvbuf and sk_sndbuf values, attacker-controlled TCP traffic can reach tcp_add_backlog(). * +1 Stronger DoS interpretation: the overflow may lead to severe backlog malfunction or kernel warning/panic behavior on systems with relevant debug or panic settings. Non-awarded signals: * No UAF, stale pointer, double free, double release, or repeated refcount mutation is established. * No controlled reclaim, arbitrary write, OOB write, type confusion, callback control, or information leak is established. * No C/I impact is awarded because the patch shows arithmetic overflow in a limit calculation, not a concrete confidentiality or integrity primitive. * No extra availability point is awarded beyond the same backlog failure/crash-style consequence. * ImportantCandidate is not set because this remains a Class C invalid-state/DoS issue without a stronger exploitation primitive. * AutoDowngradeAllowed remains YES because no unresolved Class A or strong Class B primitive is present. Repeated-release/refcount checklist: * First release can end lifetime: no such operation. * Exact same reference survives: not applicable. * Second operation is a real lifetime/refcount mutation: no. * +1 Concrete repeated release/refcount awarded: no. * Paranoid repeated-refcount leverage +1 awarded: no. * FLOOR 5 applied: no. 3. Reachability analysis A remote peer can send TCP traffic that reaches the general receive/backlog path, but the overflow requires unusually large socket buffer values such that sk_rcvbuf plus sk_sndbuf plus 64 KB exceeds signed int range. The remote attacker does not normally control those socket buffer settings directly. The complete trigger therefore depends on target-side socket configuration or application behavior. It is not proven that host-admin-equivalent privilege is required, but it is also not proven that an ordinary attacker can create the full vulnerable condition on the victim. Therefore HostAdminRequired is UNKNOWN. Namespace-scoped privilege is not established. No complete namespace-scoped trigger chain is shown. No special hardware is required. No race or timing condition is involved. 4. Primitive and severity interpretation The exact primitive is signed integer overflow in the calculation of the backlog limit passed to sk_add_backlog(). This is not memory corruption by itself. It is best classified as CLASS_C because the demonstrated behavior is invalid arithmetic state with possible DoS effects. The practical consequence is TCP backlog malfunction, packet drops, warning, or kernel failure under specific configurations. The speculative consequence is broader host DoS if the overflow reliably triggers fatal kernel behavior, but no kernel memory corruption or privilege escalation primitive is supported by the patch. ImportantCandidate is NO because there is no Class A primitive and no Class B lifetime/corruption primitive requiring Important-vs-Moderate review. AutoDowngradeAllowed is YES because the issue can be handled as a conditional DoS/integer-overflow bug unless external evidence later demonstrates stronger effects. Likely operational severity is borderline Moderate. It is worth manual review due to TCP-path exposure and possible remote triggering under preconfigured large-buffer conditions, but it is not an Important-class candidate from the supplied evidence. 5. One-sentence report phrase A signed integer overflow in tcp_add_backlog() can miscompute the TCP backlog limit when socket buffers are extremely large, allowing a remote peer to cause denial of service only on systems where such target sockets are already configured. 6. Manual review recommendation MANUAL CHECK RECOMMENDED Reason: the bug is in a common TCP path and has a defensible conditional remote DoS scenario, but no memory corruption, UAF, information leak, or privilege escalation primitive is established. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: tcp: fix a signed-integer-overflow bug in tcp_add_backlog() [ Upstream Commit: 9d04b4d0feee12bce6bfe37f30d8e953d3c30368 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9d04b4d0feee12bce6bfe37f30d8e953d3c30368 Changed files: net/ipv4/tcp_ipv4.c Diff excerpt: Not included in this email. See the upstream URL for the full patch. Full patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9d04b4d0feee12bce6bfe37f30d8e953d3c30368 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2022-50865 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2022-50865 The original CVE announcement normally does not include a security-level estimate. In particular, it may not contain a CVSS assessment, an impact level, or enough information to determine whether the reported bug is a practically relevant security issue. One purpose of this parallel CVE list is to provide that missing technical and prioritization information. The original goal of the AL-KERNEL project was to prioritize Linux kernel CVE analysis automatically before manual review. The system can also help identify non-security issues that may be suitable for automatic closure. This report was generated by AL-KERNEL, an AI-assisted Linux kernel vulnerability analysis system developed by Alexander Larkin. The first analysis stage combines an autonomous classifier with additional LLM-based analysis. The autonomous classifier runs locally on a CPU and is based on a backpropagation neural network. Together, these mechanisms produce a technical vulnerability description, identify likely weakness types, estimate CVSS severity, and provide input for ActionableScore. Two CVSS estimates are retained because incomplete kernel vulnerability information often permits more than one defensible interpretation: Conservative CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS vector: AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 5.9 The conservative vector represents a lower-impact interpretation. The Best/paranoid vector intentionally represents a plausible upper-bound interpretation and should not automatically be treated as demonstrated real-world impact. CVSS may also need to be adjusted for a particular Linux deployment, because actual reachability, privileges, enabled kernel configuration, hardware, namespaces, exposed device nodes, and other environmental conditions can differ significantly between systems. A separate ActionableScore mechanism evaluates practical remediation urgency. Its analysis may include reachability, attack prerequisites, subsystem exposure, memory-corruption characteristics, denial-of-service reliability, and possible confidentiality, integrity, or privilege-escalation impact. Conservative ActionableScore: 2 Paranoid ActionableScore: 4 The final base severity is taken directly from the second tab-separated field of the AL-KERNEL classification result. ActionableScore does not replace or independently override that final AL-KERNEL decision, and if ActionableScore adjusted impact level of ALKERNEL, then you would see self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7. For an AL-KERNEL result of MODERATE, this report uses the following additional presentation split: ActionableScore below 5 -> MODERATE REGULAR ActionableScore 5 or more -> MODERATE 7.0 The distinction between MODERATE REGULAR and MODERATE 7.0 makes it possible to identify Moderate issues that should receive manual analysis and fixes before lower-priority MODERATE REGULAR issues. In many cases, MODERATE REGULAR fixes may wait for a later rebase or routine update. There is one override in which MODERATE REGULAR becomes MODERATE 7.0 even when the ActionableScore is below 5. When the AL-KERNEL result contains the KPANIC flag, a MODERATE result is always presented as MODERATE 7.0. The KPANIC flag selected with few regexps without usage of AI at all, so it helps to detect cases when Kernel Crash happens and similar (to filter False-Negative results from the LLM usage). KPANIC indicates that a reliable kernel crash, kernel panic, or similarly serious kernel availability impact was identified by the classification workflow. AL-KERNEL base severity for this report: MODERATE KPANIC detected for this report: NO Published priority for this report (same as in Subject): MODERATE REGULAR These results are intended to support engineering triage. They are machine-generated estimates, and cases marked for manual review should be validated by a human security engineer before final disposition. For more info read docs linked from here: https://kernelcve.org/ (and you can submit you own patch there to generate such a report for non-existant CVE-id yet). Note that in many cases this AI tool selects higher severity, than real is (means you can expect Importants instead of Moderate 7.0 or Moderates 7.0 instead of regular Moderates). If you see such cases, please use reply email interface to add additional manual analyses info to this particular CVE. And please, please, let me know when you see Lows instead of Importants or Important instead of Low (because particular for such cases I need to tune this AI tool to make it better for this one and next similar). My contact email for such notifications is alexanjelausa@gmail.com (and both send reply to CVE record itself too and see "reply" button below for howto reply).