CVE-2025-21635: Linux kernel · rds: sysctl: rds_tcp_{rcv,snd}buf: avoid using current->nsproxy
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 6.8.0-1029.31~22.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 16% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1029.31~22.04.1, 6.8.0-1029.34~22.04.1, 6.8.0-1030.32~22.04.1 +31
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jan 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 to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux@6.8.0-60.63?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws@6.8.0-1029.31?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure@6.8.0-1029.34?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11@6.11.0-1012.12~24.04.1?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia@6.8.0-1016.17?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp@6.8.0-1030.32?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: rds: sysctl: rds_tcp_{rcv,snd}buf: avoid using current->nsproxy As mentioned in a previous commit of this series, using the 'net' structure via 'current' is not recommended for different reasons: - Inconsistency: getting info from the reader's/writer's netns vs only from the opener's netns. - current->nsproxy can be NULL in some cases, resulting in an 'Oops' (null-ptr-deref), e.g. when the current task is exiting, as spotted by syzbot [1] using acct(2). The per-netns structure can be obtained from the table->data using container_of(), then the 'net' one can be retrieved from the listen socket (if available).
References
- ubuntu.com/security/CVE-2025-21635 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-21635 (opens in a new tab)
- git.kernel.org/linus/7f5611cbc4871c7fb1ad36c2e5a9edad63dca95c (opens in a new tab)
- git.kernel.org/stable/c/7f5611cbc4871c7fb1ad36c2e5a9edad63dca95c (opens in a new tab)
- git.kernel.org/stable/c/de8d6de0ee27be4b2b1e5b06f04aeacbabbba492 (opens in a new tab)
- ubuntu.com/security/notices/USN-7379-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7380-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7381-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7382-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7379-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7513-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7513-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7514-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7515-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7513-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7522-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7515-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7523-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7524-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7513-4 (opens in a new tab)