CVE-2025-39990: Linux kernel · bpf: Check the helper function is valid in get_helper_proto
Source GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in e4414b01c1cd9887bbde92f946c1ba94e40d6d64 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in e4414b01c1cd9887bbde92f946c1ba94e40d6d64, dfbff47f120e4b0793ca0e0b8660361ccac25a74, 6233715b4b714068d6c831d214a4e8792109875a +1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 15 Oct 2025
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 Linux kernel to e4414b01c1cd9887bbde92f946c1ba94e40d6d64, dfbff47f120e4b0793ca0e0b8660361ccac25a74, 6233715b4b714068d6c831d214a4e8792109875a or 3d429cb1278e995e22995ef117fa96d223a67e93.
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– |
AI-suggested
A fix has been implemented in the Linux kernel to address this vulnerability by validating the helper function in get_helper_proto and marking the tail_call helper function as poisoned. Users should apply the official Linux kernel updates that include this fix. Patch status is not explicitly confirmed in the provided data; therefore, check the vendor advisory or Linux kernel mailing lists for the latest remediation guidance.
Description
A high severity vulnerability in the Linux kernel related to the BPF subsystem was resolved. The issue involved a verifier bug where a helper function pointer could be NULL due to a disabled configuration option. The fix involves validating the helper function directly in get_helper_proto and marking the tail_call helper function as poisoned since it is unused by design.
References
- nvd.nist.gov/vuln/detail/CVE-2025-39990 (opens in a new tab)
- git.kernel.org/stable/c/3d429cb1278e995e22995ef117fa96d223a67e93 (opens in a new tab)
- git.kernel.org/stable/c/6233715b4b714068d6c831d214a4e8792109875a (opens in a new tab)
- git.kernel.org/stable/c/e4414b01c1cd9887bbde92f946c1ba94e40d6d64 (opens in a new tab)