CyberSecBulletin
CVE-2026-64551NVD status: Analyzed

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2026-64551 is a critical-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 6022da37786701df1fc5dd946a6dcba59d5473b1, 861f884f5471632c731cbbd612a1c072e391a624, 588706ebaf8cdb4a4161602949eba365514b1db1 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 0.51% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Linux to 6022da37786701df1fc5dd946a6dcba59d5473b1 or 861f884f5471632c731cbbd612a1c072e391a624 or 588706ebaf8cdb4a4161602949eba365514b1db1 or a257b41ddfe9e327b26581ad2777f04b23ac73f5, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.261 or 5.15.212 or 6.1.178 or 6.6.145, whichever matches your release line, or a later version.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 6022da37786701df1fc5dd946a6dcba59d5473b1; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 861f884f5471632c731cbbd612a1c072e391a624; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 588706ebaf8cdb4a4161602949eba365514b1db1; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, a257b41ddfe9e327b26581ad2777f04b23ac73f5; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 08a8f2d13f703924316e9aeac863a88ef50990c7; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, ebe0a55d954fa8da383b6192edb8f763dcb002d5; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, bbd6b2ea966cf57b6ae095cf5a8dbc993cd197a0; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 1cd23ca80784223fa2204e16203f754da4e821f8; and 1 more ranges6022da37786701df1fc5dd946a6dcba59d5473b1, 861f884f5471632c731cbbd612a1c072e391a624, 588706ebaf8cdb4a4161602949eba365514b1db1, a257b41ddfe9e327b26581ad2777f04b23ac73f5, 08a8f2d13f703924316e9aeac863a88ef50990c7, ebe0a55d954fa8da383b6192edb8f763dcb002d5
LinuxLinux Kernel2.6.12.1 up to, but not including, 5.10.261; 5.11 up to, but not including, 5.15.212; 5.16 up to, but not including, 6.1.178; 6.2 up to, but not including, 6.6.145; 6.7 up to, but not including, 6.12.97; 6.13 up to, but not including, 6.18.40; 6.19 up to, but not including, 7.1.5; 2.6.12; and 1 more ranges5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40

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
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
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
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: sctp: validate STALE_COOKIE cause length before reading staleness When an ERROR chunk with a STALE_COOKIE cause is received in the COOKIE_ECHOED state, sctp_sf_do_5_2_6_stale() reads the 4-byte Measure of Staleness that follows the cause header: err = (struct sctp_errhdr *)(chunk->skb->data); stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); err is the first cause in the chunk, not the STALE_COOKIE cause that caused the dispatch, and nothing guarantees the staleness field is present. sctp_walk_errors() only requires a cause to be as long as the 4-byte header, so for a STALE_COOKIE cause of length 4 the read runs past the cause, and for a minimal ERROR chunk past skb->tail. The value is echoed to the peer in the Cookie Preservative of the reply INIT, leaking uninitialized memory. sctp_sf_cookie_echoed_err() already walks to the STALE_COOKIE cause, so check its length there and pass it to sctp_sf_do_5_2_6_stale(), which reads that cause instead of the first one. A STALE_COOKIE cause too short to hold the staleness field is discarded. The read is reachable by any peer that can drive an association into COOKIE_ECHOED, including an unprivileged process using a raw SCTP socket in a user and network namespace.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

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