Linux: Missing Release of Memory after Effective Lifetime
CVE-2026-52923 is a high-severity missing release of memory after effective lifetime vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 3bbe2bb9111ce6967a951bfac79af142d816fae5, 8c58a92849175f5e2ab7bc2734b3b89afe79f6ef, af24e202b543ded8a34f1d5d3db54eb916173f04 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.21% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 3bbe2bb9111ce6967a951bfac79af142d816fae5 or 8c58a92849175f5e2ab7bc2734b3b89afe79f6ef or af24e202b543ded8a34f1d5d3db54eb916173f04 or 157ce2c6836ce0ff19108a819f38df061345425f, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.259 or 5.15.210 or 6.1.176 or 6.6.143, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 03f595668017f1a1fb971c02fc37140bc6e7bb1c up to, but not including, 3bbe2bb9111ce6967a951bfac79af142d816fae5; 03f595668017f1a1fb971c02fc37140bc6e7bb1c up to, but not including, 8c58a92849175f5e2ab7bc2734b3b89afe79f6ef; 03f595668017f1a1fb971c02fc37140bc6e7bb1c up to, but not including, af24e202b543ded8a34f1d5d3db54eb916173f04; 03f595668017f1a1fb971c02fc37140bc6e7bb1c up to, but not including, 157ce2c6836ce0ff19108a819f38df061345425f; 03f595668017f1a1fb971c02fc37140bc6e7bb1c up to, but not including, 41058d4c3f63ab64901560a704882e0565f4e456; 03f595668017f1a1fb971c02fc37140bc6e7bb1c up to, but not including, a3cc795129e5ec0f8948653a3bf471e7d8852f5e; 03f595668017f1a1fb971c02fc37140bc6e7bb1c up to, but not including, bd4be70669af55b974860d13680348cfdf50bbed; 03f595668017f1a1fb971c02fc37140bc6e7bb1c up to, but not including, fa0b9b2b7ae3539908d69c2b9ac0d144d9bc5139; and 1 more ranges | 3bbe2bb9111ce6967a951bfac79af142d816fae5, 8c58a92849175f5e2ab7bc2734b3b89afe79f6ef, af24e202b543ded8a34f1d5d3db54eb916173f04, 157ce2c6836ce0ff19108a819f38df061345425f, 41058d4c3f63ab64901560a704882e0565f4e456, a3cc795129e5ec0f8948653a3bf471e7d8852f5e |
| Red Hat | Red Hat Enterprise Linux 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | all versions | Not stated |
| Linux | Linux Kernel | 3.8.1 up to, but not including, 5.10.259; 5.11 up to, but not including, 5.15.210; 5.16 up to, but not including, 6.1.176; 6.2 up to, but not including, 6.6.143; 6.7 up to, but not including, 6.12.93; 6.13 up to, but not including, 6.18.35; 6.19 up to, but not including, 7.0.12; 3.8; and 1 more ranges | 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | CNA |
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Release of Memory after Effective Lifetime
The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
How developers prevent this class of flaw
- Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone. For example, glibc in Linux provides protection against free of invalid pointers. When using Xcode to target OS X or iOS, enable automatic reference counting (ARC). To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std
- Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Consider using the Boehm-Demers-Weiser garbage collector (bdwgc), which can help avoid leaks.
More Missing Release of Memory after Effective Lifetime vulnerabilities (CWE-401)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/157ce2c6836ce0ff19108a819f38df061345425f
- git.kernel.org/stable/c/3bbe2bb9111ce6967a951bfac79af142d816fae5
- git.kernel.org/stable/c/41058d4c3f63ab64901560a704882e0565f4e456
- git.kernel.org/stable/c/8c58a92849175f5e2ab7bc2734b3b89afe79f6ef
- git.kernel.org/stable/c/a3cc795129e5ec0f8948653a3bf471e7d8852f5e
- git.kernel.org/stable/c/af24e202b543ded8a34f1d5d3db54eb916173f04
- git.kernel.org/stable/c/bd4be70669af55b974860d13680348cfdf50bbed
- git.kernel.org/stable/c/fa0b9b2b7ae3539908d69c2b9ac0d144d9bc5139
Third-party and government advisories
- access.redhat.com/security/cve/CVE-2026-52923Third Party Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2492094Issue Tracking, Third Party Advisory
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52923.jsonThird Party Advisory
Other references
- access.redhat.com/errata/RHSA-2026:47248
- access.redhat.com/errata/RHSA-2026:48386
- access.redhat.com/errata/RHSA-2026:49031
- access.redhat.com/errata/RHSA-2026:49212
- access.redhat.com/errata/RHSA-2026:49851
- access.redhat.com/errata/RHSA-2026:49857
- access.redhat.com/errata/RHSA-2026:51603
- access.redhat.com/errata/RHSA-2026:51604
- access.redhat.com/errata/RHSA-2026:52649
- access.redhat.com/errata/RHSA-2026:52764
- access.redhat.com/errata/RHSA-2026:53330
- access.redhat.com/errata/RHSA-2026:61692
- access.redhat.com/errata/RHSA-2026:63189
- cert-portal.siemens.com/productcert/html/ssa-784472.html
Recent Missing Release of Memory after Effective Lifetime vulnerabilities
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