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CVE-2026-49422

Use-after-free in TCP RACK stack option handler

High8.4EPSS 0.17%
Published
Updated
Reserved
Assigned by
freebsd

Description

The RACK setsockopt(2) handler drops the connection lock in order to copy option data from userspace, then reacquires the lock. After reacquiring, it verifies that the TCP stack had not been switched away, but did not reload its pointer to the stack's per-connection control block. If userspace switches stacks twice during this window, the check will succeed but the saved pointer will refer to freed memory. The bug may be exploitable by an unprivileged local user to escalate privileges.

Scores

CVSS scores of CVE-2026-49422, by who scored it
Scored byCVSSScoreVector
CISA-ADPADP (enrichment)3.1High8.4CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVDNVD · Analyzed3.1High8.4CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (exploitation in 30 days)
0.17% · top 94% of all CVEs (6 Nov 2026)
CISA SSVC
Exploitation: none · Automatable: no · Technical impact: total
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.4.

Weakness

Affected products

  • FreeBSD · FreeBSD

    • affected 15.1-RELEASE – < p1
    • affected 15.0-RELEASE – < p11
    • affected 14.4-RELEASE – < p7
    • affected 14.3-RELEASE – < p16

References (1)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .