ipc: limit next_id allocation to the valid ID range

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Summary

CVECVE-2026-52923
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-24 08:16:22 UTC
Updated2026-07-10 12:17:09 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 5.8 MEDIUM from ADP

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H

EPSS: 0.001250000 probability, percentile 0.026110000 (date 2026-07-09)

Problem Types: CWE-401 | CWE-825 | CWE-825 Expired Pointer Dereference

VersionSourceTypeScoreSeverityVector
3.1ADPCVSS5.8MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.10b0ca135-0b70-47e7-9f44-1890c2a1c46cSecondary5.8MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
High

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 03f595668017f1a1fb971c02fc37140bc6e7bb1c 3bbe2bb9111ce6967a951bfac79af142d816fae5 git Not specified
CNA Linux Linux affected 03f595668017f1a1fb971c02fc37140bc6e7bb1c 8c58a92849175f5e2ab7bc2734b3b89afe79f6ef git Not specified
CNA Linux Linux affected 03f595668017f1a1fb971c02fc37140bc6e7bb1c af24e202b543ded8a34f1d5d3db54eb916173f04 git Not specified
CNA Linux Linux affected 03f595668017f1a1fb971c02fc37140bc6e7bb1c 157ce2c6836ce0ff19108a819f38df061345425f git Not specified
CNA Linux Linux affected 03f595668017f1a1fb971c02fc37140bc6e7bb1c 41058d4c3f63ab64901560a704882e0565f4e456 git Not specified
CNA Linux Linux affected 03f595668017f1a1fb971c02fc37140bc6e7bb1c a3cc795129e5ec0f8948653a3bf471e7d8852f5e git Not specified
CNA Linux Linux affected 03f595668017f1a1fb971c02fc37140bc6e7bb1c bd4be70669af55b974860d13680348cfdf50bbed git Not specified
CNA Linux Linux affected 03f595668017f1a1fb971c02fc37140bc6e7bb1c fa0b9b2b7ae3539908d69c2b9ac0d144d9bc5139 git Not specified
CNA Linux Linux affected 3.8 Not specified
CNA Linux Linux unaffected 3.8 semver Not specified
CNA Linux Linux unaffected 5.10.259 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.210 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.176 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.143 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.93 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.35 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.12 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1 * original_commit_for_fix Not specified
ADP Red Hat Red Hat Enterprise Linux 10 Not specified Not specified
ADP Red Hat Red Hat Enterprise Linux 7 Not specified Not specified
ADP Red Hat Red Hat Enterprise Linux 8 Not specified Not specified
ADP Red Hat Red Hat Enterprise Linux 9 Not specified Not specified
ADP Red Hat Red Hat Enterprise Linux 6 Not specified Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/41058d4c3f63ab64901560a704882e0565f4e456 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/bd4be70669af55b974860d13680348cfdf50bbed 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/af24e202b543ded8a34f1d5d3db54eb916173f04 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
bugzilla.redhat.com/show_bug.cgi 0b0ca135-0b70-47e7-9f44-1890c2a1c46c bugzilla.redhat.com Issue Tracking, Third Party Advisory
git.kernel.org/stable/c/a3cc795129e5ec0f8948653a3bf471e7d8852f5e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/3bbe2bb9111ce6967a951bfac79af142d816fae5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/157ce2c6836ce0ff19108a819f38df061345425f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
access.redhat.com/security/cve/CVE-2026-52923 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com Third Party Advisory
git.kernel.org/stable/c/fa0b9b2b7ae3539908d69c2b9ac0d144d9bc5139 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/8c58a92849175f5e2ab7bc2734b3b89afe79f6ef 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52923.json 0b0ca135-0b70-47e7-9f44-1890c2a1c46c security.access.redhat.com Third Party Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

SourceTimeEvent
ADP2026-06-24T00:00:00.000ZReported to Red Hat.
ADP2026-06-24T00:00:00.000ZMade public.
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