CVE-2026-46158
Analyzed Analyzed - Analysis Complete
MPTCP ADD_ADDR retransmission sk refcount leak fix

Publication date: 2026-05-28

Last updated on: 2026-06-09

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: mptcp: pm: ADD_ADDR rtx: always decrease sk refcount When an ADD_ADDR is retransmitted, the sk is held in sk_reset_timer(). It should then be released in all cases at the end. Some (unlikely) checks were returning directly instead of calling sock_put() to decrease the refcount. Jump to a new 'exit' label to call __sock_put() (which will become sock_put() in the next commit) to fix this potential leak. While at it, drop the '!msk' check which cannot happen because it is never reset, and explicitly mark the remaining one as "unlikely".
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Meta Information
Published
2026-05-28
Last Modified
2026-06-09
Generated
2026-06-17
AI Q&A
2026-05-28
EPSS Evaluated
2026-06-16
NVD
CVE-2026-46158
EUVD
EUVD-2026-32785
Affected Vendors & Products
Showing 6 associated CPEs
Vendor Product Version / Range
linux linux_kernel 7.1
linux linux_kernel 7.1
linux linux_kernel From 6.13 (inc) to 6.18.30 (exc)
linux linux_kernel From 6.19 (inc) to 7.0.7 (exc)
linux linux_kernel From 5.10 (inc) to 6.6.142 (exc)
linux linux_kernel From 6.7 (inc) to 6.12.92 (exc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's Multipath TCP (mptcp) implementation, specifically in the handling of the ADD_ADDR retransmission timer (rtx). When an ADD_ADDR message is retransmitted, a socket reference (sk) is held in sk_reset_timer(). However, in some rare cases, the reference count for this socket was not properly decreased because certain checks returned early without calling sock_put(), which is responsible for releasing the socket reference. This could lead to a potential resource leak. The fix involves ensuring that sock_put() is always called by jumping to a common exit label, thereby properly decreasing the socket reference count.

Impact Analysis

The vulnerability can cause a resource leak in the Linux kernel's networking stack due to socket references not being properly released during ADD_ADDR retransmissions in Multipath TCP. Over time, this could lead to increased memory usage and potentially degrade system performance or stability if the leak accumulates. However, the description notes that the problematic checks are unlikely to occur, suggesting the impact might be limited or rare.

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