CVE-2026-63919 (CVSS 8.8)

Description

In the Linux kernel, the following vulnerability has been resolved: xfrm: input: hold netns during deferred transport reinjection Transport-mode reinjection stores a struct net pointer in skb->cb and uses it later from xfrm_trans_reinject(). That pointer must stay valid until the deferred callback runs. Take a netns reference when queueing deferred reinjection work and drop it after the callback completes. Use maybe_get_net() so the queueing path does not revive a namespace that is already being torn down. This keeps the existing workqueue design and fixes the netns lifetime handling in one place for all users of xfrm_trans_queue_net().

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CVSS v3.1 Score

8.8

HIGH

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

EPSS — Exploit Prediction

0.0063

Probability of exploitation

0.46%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/2df7059a18afb7d3aee6c36cad5d371c198111d4 https://git.kernel.org/stable/c/48ce101cd630d6745b6923b5bad8358bc4c119da https://git.kernel.org/stable/c/55ddfc41451f01c588089cd74957a05311b6f202 https://git.kernel.org/stable/c/7ee59eda8820b758ed29e1cd3222359c7b97302c https://git.kernel.org/stable/c/8dfabcba6a943a7a02ebe1e1637c361ba96acbaa https://git.kernel.org/stable/c/9f67a36e91bb50d358760f381f233913fe5c09f8 https://git.kernel.org/stable/c/9f7ebb45a83afc3216e855e57d51bb4bc9b5232e https://git.kernel.org/stable/c/c16f74dc1d75d0e2e7670076d5375deda110ebeb

Frequently Asked Questions

What is CVE-2026-63919? +

In the Linux kernel, the following vulnerability has been resolved: xfrm: input: hold netns during deferred transport reinjection Transport-mode reinjection stores a struct net pointer in skb->cb and uses it later from xfrm_trans_reinject(). That pointer must stay valid until the deferred callback runs. Take a netns reference when queueing deferred reinjection work and drop it after the callback completes. Use maybe_get_net() so the queueing path does not revive a namespace that is already being torn down. This keeps the existing workqueue design and fixes the netns lifetime handling in one place for all users of xfrm_trans_queue_net(). It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-63919? +

CVE-2026-63919 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0063, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-63919? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

CVE-2026-63919