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CVE-2026-64551

CRITICALCVSS 9.1/10EPSS 0.18%

Last modified

CVE-2026-64551 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. 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. EPSS estimates a 0.18% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
9.1/10

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

EPSS Probability
0.18%

7.4th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 6022da37786701df1fc5dd946a6dcba59d5473b1; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 861f884f5471632c731cbbd612a1c072e391a624; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 588706ebaf8cdb4a4161602949eba365514b1db1; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < a257b41ddfe9e327b26581ad2777f04b23ac73f5; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 08a8f2d13f703924316e9aeac863a88ef50990c7; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < ebe0a55d954fa8da383b6192edb8f763dcb002d5; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < bbd6b2ea966cf57b6ae095cf5a8dbc993cd197a0; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 1cd23ca80784223fa2204e16203f754da4e821f8
LinuxLinux2.6.12

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-64551?
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.
How severe is CVE-2026-64551?
CVE-2026-64551 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.18% probability of exploitation in the next 30 days.
How do I fix CVE-2026-64551?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST