CVE-2026-52923 — ipc: limit next_id allocation to the valid ID range
In the Linux kernel, the following vulnerability has been resolved: ipc: limit next_id allocation to the valid ID range The checkpoint/restore sysctl path can request the next SysV IPC id through ids->next_id. ipc_idr_alloc() currently forwards that request to idr_alloc() with an open-ended upper bound. If the valid tail of the SysV IPC id space is full, the allocation can spill beyond ipc_mni. The returned SysV IPC id still uses the normal index encoding, so later lookup and removal can target the wrong slot. This leaves the real IDR entry behind and breaks the IDR state for the object. The bug is in ipc_idr_alloc() in the checkpoint/restore path. 1. ids->next_id is passed to: idr_alloc(&ids->ipcs_idr, new, ipcid_to_idx(next_id), 0, ...) 2. The zero upper bound makes the allocation effectively open-ended. Once the valid SysV IPC tail is occupied, idr_alloc() can spill past ipc_mni and allocate an entry beyond the valid IPC id range. 3. The new object id is still encoded with the narrower SysV IPC index width: new->id = (new->seq << ipcmni_seq_shift()) + idx 4. Later removal goes through ipc_rmid(), which uses: ipcid_to_idx(ipcp->id) That truncates the real IDR index. An object actually stored at a high index can then be removed as if it lived at a low in-range index. 5. For shared memory, shm_destroy() frees the current object anyway, but the real high IDR slot is left behind as a dangling pointer. 6. A subsequent walk of /proc/sysvipc/shm reaches the stale IDR entry and dereferences freed memory. Prevent this by bounding the requested allocation to ipc_mni so the checkpoint/restore path fails once the valid range is exhausted.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+1
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
version 3.8≥ 03f595668017f1a1fb971c02fc37140bc6e7bb1c and < fa0b9b2b7ae3539908d69c2b9ac0d144d9bc5139≥ 03f595668017f1a1fb971c02fc37140bc6e7bb1c and < bd4be70669af55b974860d13680348cfdf50bbed≥ 03f595668017f1a1fb971c02fc37140bc6e7bb1c and < a3cc795129e5ec0f8948653a3bf471e7d8852f5e≥ 03f595668017f1a1fb971c02fc37140bc6e7bb1c and < 41058d4c3f63ab64901560a704882e0565f4e456≥ 03f595668017f1a1fb971c02fc37140bc6e7bb1c and < 157ce2c6836ce0ff19108a819f38df061345425f≥ 03f595668017f1a1fb971c02fc37140bc6e7bb1c and < af24e202b543ded8a34f1d5d3db54eb916173f04≥ 03f595668017f1a1fb971c02fc37140bc6e7bb1c and < 8c58a92849175f5e2ab7bc2734b3b89afe79f6ef and 1 more≥ 03f595668017f1a1fb971c02fc37140bc6e7bb1c and < 3bbe2bb9111ce6967a951bfac79af142d816fae5 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel |
version 7.1-rc1version 7.1-rc5version 7.1-rc4version 7.1-rc3version 7.1-rc2≥ 3.8.1 and < 5.10.259version 3.8-rc7version 3.8-rc6 and 10 moreversion 3.8-rc5version 3.8-rc4version 3.8-rc3version 3.8≥ 6.19 and < 7.0.12≥ 6.13 and < 6.18.35≥ 6.7 and < 6.12.93≥ 6.2 and < 6.6.143≥ 5.16 and < 6.1.176≥ 5.11 and < 5.15.210 |
Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.8 | CVSS 3.1 | High | 1.8 | 5.9 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database |
| 7.8 | CVSS 3.1 | High | 1.8 | 5.9 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c via NIST National Vulnerability Database |
| 7.8 | CVSS 3.1 | High | — | — | GitHub, Inc. via GitHub Security Advisories |
| 7.8 | CVSS 3.1 | High | — | — | Linux via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
CWE-401 · Missing Release of Memory after Effective Lifetime
EPSS over time FIRST
Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.17%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · linux/linux
- Record published
- Fix documented
- CVSS changed · 7.8
- Source status changed · → Modified
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 14, 2026 – Oct 15, 2026
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
27 on the record
- git.kernel.org/stable/c/fa0b9b2b7ae3539908d69c2b9ac0d144d9bc5139
- git.kernel.org/stable/c/157ce2c6836ce0ff19108a819f38df061345425f
- git.kernel.org/stable/c/bd4be70669af55b974860d13680348cfdf50bbed
- git.kernel.org/stable/c/a3cc795129e5ec0f8948653a3bf471e7d8852f5e
- git.kernel.org/stable/c/8c58a92849175f5e2ab7bc2734b3b89afe79f6ef
- git.kernel.org/stable/c/3bbe2bb9111ce6967a951bfac79af142d816fae5
- git.kernel.org/stable/c/41058d4c3f63ab64901560a704882e0565f4e456
- git.kernel.org/stable/c/af24e202b543ded8a34f1d5d3db54eb916173f04
- access.redhat.com/errata/RHSA-2026:53330
- access.redhat.com/errata/RHSA-2026:61692
- access.redhat.com/security/cve/CVE-2026-52923
- cert-portal.siemens.com/productcert/html/ssa-784472.html
- access.redhat.com/errata/RHSA-2026:49857
- access.redhat.com/errata/RHSA-2026:49212
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52923.json
- access.redhat.com/errata/RHSA-2026:49031
- bugzilla.redhat.com/show_bug.cgi
- access.redhat.com/errata/RHSA-2026:48386
- github.com/advisories/GHSA-m237-4jxg-w5jh
- access.redhat.com/errata/RHSA-2026:47248
- access.redhat.com/errata/RHSA-2026:49851
- access.redhat.com/errata/RHSA-2026:63189
- nvd.nist.gov/vuln/detail/CVE-2026-52923
- access.redhat.com/errata/RHSA-2026:51604
- access.redhat.com/errata/RHSA-2026:52649
- access.redhat.com/errata/RHSA-2026:51603
- access.redhat.com/errata/RHSA-2026:52764
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 15h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 15h
- Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
- Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
- Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
- Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No CISA SSVC assessment.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-52923 is "ipc: limit next_id allocation to the valid ID range", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 0.17% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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