CVE-2026-99059: Linux kernel · wireguard: noise: reject response consumption after intermediate initiation
Source GCVE Database
Not known to be exploited · CVSS 7.7 High · fixed in fb5ce4c7790c3eeec820302d08d70ecf46af4295 : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in fb5ce4c7790c3eeec820302d08d70ecf46af4295, d0305f8d90029556260c6824b61c493c424eba9e, c76a80db593096edf2b3b3972f58b6342a8c6c04 +2
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:LExploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
Description
In the Linux kernel, the following vulnerability has been resolved: wireguard: noise: reject response consumption after intermediate initiation Two threads begin processing the identical response message, received twice. The first thread, A, runs. While it's running, the second one, B, gets partway through, and during that slow calculation, or even while blocking on down_write(), A completes and then also a handshake initiation that's already been queued up runs in thread C, which itself takes that same down_write(). The handshake initiation creation succeeds, and sets the state back to waiting-for-response, and calls up_write(), at which point thread B resumes, because either its finished its calculations or was finally allowed to acquire down_write(). Thread B then copies the state back to the peer, and begins a new session, using that state, which is the same session as the one made in thread A. Thread A Thread B Thread C down_read() sA = handshake->state memcpy(cA, handshake->crypto) up_read() if (sA != 1) goto fail slow_crypto(cA) down_read() sB = handshake->state memcpy(cB, handshake->crypto) up_read() if (sB != 1) goto fail slow_crypto(cB) down_write() if (sA != handshake->state) goto fail memcpy(handshake->crypto, cA) handshake->state = 2 up_write() down_write() if (handshake->state != 2) goto fail derive_session(handshake->crypto) up_write() down_write() slow_crypto(handshake->crypto) handshake->state = 1 up_write() down_write() if (sB != handshake->state) goto fail memcpy(handshake->crypto, cB) handshake->state = 2 up_write() down_write() if (handshake->state != 2) goto fail derive_session(handshake->crypto) up_write() This seems basically impossible to hit in a meaningful way in practice, but ensure that it absolutely cannot happen by comparing the ephemeral private key that's on the stack with the latest one that the peer's handshake state has.
References
- nvd.nist.gov/vuln/detail/CVE-2026-99059 (opens in a new tab)
- git.kernel.org/stable/c/3bec3d32c2a3afd164fc87f95457df2cf9049c20 (opens in a new tab)
- git.kernel.org/stable/c/4d64a3d6e96aa78619c9c29ffde309794974588a (opens in a new tab)
- git.kernel.org/stable/c/c76a80db593096edf2b3b3972f58b6342a8c6c04 (opens in a new tab)
- git.kernel.org/stable/c/d0305f8d90029556260c6824b61c493c424eba9e (opens in a new tab)
- git.kernel.org/stable/c/fb5ce4c7790c3eeec820302d08d70ecf46af4295 (opens in a new tab)