CVE-2024-26923

Advisory lineage Upstream: 0 Downstream: 248
Modified
Published: 24 Apr 2024, 21:49
Last modified:12 May 2026, 11:50

Vulnerability Summary

Overall Risk (default)
low
19/100
CVSS Score
4.7 MEDIUM
v3.1 (nvd)
EPSS Score
0.01% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

24 Apr 2024, 21:49
Published
Vulnerability first disclosed
12 May 2026, 11:50
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: af_unix: Fix garbage collector racing against connect() Garbage collector does not take into account the risk of embryo getting enqueued during the garbage collection. If such embryo has a peer that carries SCM_RIGHTS, two consecutive passes of scan_children() may see a different set of children. Leading to an incorrectly elevated inflight count, and then a dangling pointer within the gc_inflight_list. sockets are AF_UNIX/SOCK_STREAM S is an unconnected socket L is a listening in-flight socket bound to addr, not in fdtable V's fd will be passed via sendmsg(), gets inflight count bumped connect(S, addr) sendmsg(S, [V]); close(V) __unix_gc() ---------------- ------------------------- ----------- NS = unix_create1() skb1 = sock_wmalloc(NS) L = unix_find_other(addr) unix_state_lock(L) unix_peer(S) = NS // V count=1 inflight=0 NS = unix_peer(S) skb2 = sock_alloc() skb_queue_tail(NS, skb2[V]) // V became in-flight // V count=2 inflight=1 close(V) // V count=1 inflight=1 // GC candidate condition met for u in gc_inflight_list: if (total_refs == inflight_refs) add u to gc_candidates // gc_candidates={L, V} for u in gc_candidates: scan_children(u, dec_inflight) // embryo (skb1) was not // reachable from L yet, so V's // inflight remains unchanged __skb_queue_tail(L, skb1) unix_state_unlock(L) for u in gc_candidates: if (u.inflight) scan_children(u, inc_inflight_move_tail) // V count=1 inflight=2 (!) If there is a GC-candidate listening socket, lock/unlock its state. This makes GC wait until the end of any ongoing connect() to that socket. After flipping the lock, a possibly SCM-laden embryo is already enqueued. And if there is another embryo coming, it can not possibly carry SCM_RIGHTS. At this point, unix_inflight() can not happen because unix_gc_lock is already taken. Inflight graph remains unaffected.

CVSS Metrics

  • v3.1•MEDIUM•Score: 4.7CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.01%• Percentile: 2%

Techniques & Countermeasures

  • CWE-362•Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

    The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

Affected Systems

  • debian•debian_linux

    10.0

  • linux•linux

    ≥ 1fd05ba5a2f2aa8e7b9b52ef55df850e2e7d54c9, < a36ae0ec2353015f0f6762e59f4c2dbc0c906423 | ≥ 1fd05ba5a2f2aa8e7b9b52ef55df850e2e7d54c9, < 343c5372d5e17b306db5f8f3c895539b06e3177f | ≥ 1fd05ba5a2f2aa8e7b9b52ef55df850e2e7d54c9, < 2e2a03787f4f0abc0072350654ab0ef3324d9db3 | ≥ 1fd05ba5a2f2aa8e7b9b52ef55df850e2e7d54c9, < e76c2678228f6aec74b305ae30c9374cc2f28a51 | ≥ 1fd05ba5a2f2aa8e7b9b52ef55df850e2e7d54c9, < b75722be422c276b699200de90527d01c602ea7c | ≥ 1fd05ba5a2f2aa8e7b9b52ef55df850e2e7d54c9, < 507cc232ffe53a352847893f8177d276c3b532a9 | ≥ 1fd05ba5a2f2aa8e7b9b52ef55df850e2e7d54c9, < dbdf7bec5c920200077d693193f989cb1513f009 | ≥ 1fd05ba5a2f2aa8e7b9b52ef55df850e2e7d54c9, < 47d8ac011fe1c9251070e1bd64cb10b48193ec51 | 2.6.23

  • linux•linux_kernel

    ≥ 2.6.23, < 4.19.314 | ≥ 4.20, < 5.4.275 | ≥ 5.5, < 5.10.216 | ≥ 5.11, < 5.15.156 | ≥ 5.16, < 6.1.87 | ≥ 6.2, < 6.6.28 | ≥ 6.7, < 6.8.7 | 6.9:rc1 | 6.9:rc2 | 6.9:rc3

References (13)