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NVD / CVE Program· CNA Linux

CVE-2023-52564: Revert "tty: n_gsm: fix UAF in gsm_cleanup_mux"

MediumCVSS 5.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.25% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 29346e217b8ab8a52889b88f00b268278d6b7668, 2bff660e0ff349dee84dc4f6f6d10da4497f5b28, 5.10.198.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 29346e217b8ab8a52889b88f00b268278d6b7668, 2bff660e0ff349dee84dc4f6f6d10da4497f5b28, 5.10.198 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: Revert "tty: n_gsm: fix UAF in gsm_cleanup_mux" This reverts commit 9b9c8195f3f0d74a826077fc1c01b9ee74907239. The commit above is reverted as it did not solve the original issue. gsm_cleanup_mux() tries to free up the virtual ttys by calling gsm_dlci_release() for each available DLCI. There, dlci_put() is called to decrease the reference counter for the DLCI via tty_port_put() which finally calls gsm_dlci_free(). This already clears the pointer which is being checked in gsm_cleanup_mux() before calling gsm_dlci_release(). Therefore, it is not necessary to clear this pointer in gsm_cleanup_mux() as done in the reverted commit. The commit introduces a null pointer dereference: <TASK> ? __die+0x1f/0x70 ? page_fault_oops+0x156/0x420 ? search_exception_tables+0x37/0x50 ? fixup_exception+0x21/0x310 ? exc_page_fault+0x69/0x150 ? asm_exc_page_fault+0x26/0x30 ? tty_port_put+0x19/0xa0 gsmtty_cleanup+0x29/0x80 [n_gsm] release_one_tty+0x37/0xe0 process_one_work+0x1e6/0x3e0 worker_thread+0x4c/0x3d0 ? __pfx_worker_thread+0x10/0x10 kthread+0xe1/0x110 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2f/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1b/0x30 </TASK> The actual issue is that nothing guards dlci_put() from being called multiple times while the tty driver was triggered but did not yet finished calling gsm_dlci_free().

Published
Mar 2, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 16th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 74a8d6f50cc90ed0061997db51dfa81a62b0f835, 6.5affected
    • 8fc0eabaa73bbd9bd705577071564616da5c8c61 and later · before 6d5c8862932d31a810b6545f7d69ecc124402c6eaffected · git
    • 5138c228311a863c3cf937b94a3ab4c87f1f70c4 and later · before a48d2bcd23f2c98d575bc2f9b7a3fbd16aeea9ebaffected · git
    • 9615ca54bc138e35353a001e8b5d4824dce72188 and later · before c61d0b87a7028c2c10faffc524d748334c7b9827affected · git
    • 9b9c8195f3f0d74a826077fc1c01b9ee74907239 and later · before 2bff660e0ff349dee84dc4f6f6d10da4497f5b28affected · git
    • 9b9c8195f3f0d74a826077fc1c01b9ee74907239 and later · before 29346e217b8ab8a52889b88f00b268278d6b7668affected · git
    • 5.10.190 and later · before 5.10.198affected · semver
    • 5.15.124 and later · before 5.15.134affected · semver
    • 6.1.43 and later · before 6.1.56affected · semver
    • 6.4.8 and later · before 6.5affected · semver
Affected versions · NVD (5)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.10.190 and later · before 5.10.198
  • linux linux kernel5.15.124 and later · before 5.15.134
  • linux linux kernel6.1.43 and later · before 6.1.56
  • linux linux kernel6.5 and later · before 6.5.6
  • linux linux kernel6.6

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.64-16.1.64-1
Debian:13linuxbefore 6.5.6-16.5.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe…KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2023-52562Mar 2, 2024 · mm/slab_common: fix slab_caches list corruption after kmem_cache_destroy()
    22Monitor
  • ← EarlierCVE-2023-52563Mar 2, 2024 · drm/meson: fix memory leak on ->hpd_notify callback
    22Monitor
  • Later →CVE-2023-52565Mar 2, 2024 · media: uvcvideo: Fix OOB read
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux29346e217b8ab8a52889b88f00b268278d6b7668Vendor (CNA)
Linux Linux2bff660e0ff349dee84dc4f6f6d10da4497f5b28Vendor (CNA)
Linux Linux5.10.198Vendor (CNA)
Linux Linux5.15.134Vendor (CNA)
Linux Linux6.1.56Vendor (CNA)
Linux Linux6.5Vendor (CNA)
Linux Linux6d5c8862932d31a810b6545f7d69ecc124402c6eVendor (CNA)
Linux Linuxa48d2bcd23f2c98d575bc2f9b7a3fbd16aeea9ebVendor (CNA)
Linux Linuxc61d0b87a7028c2c10faffc524d748334c7b9827Vendor (CNA)
debian:linux6.1.64-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records