rxrpc: proc: size address buffers for %pISpc output
CVE-2026-31630 · published 24 Apr 2026
How serious is it
- Severity: high, CVSS score 7.8 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-31630?
Paste this prompt into Claude Code, Cursor or any AI coding tool: it runs a free Shippable scan of your project and fixes what it finds. Built with Lovable, Bolt or v0? Scan your live app. Or upload your package file.
Who is affected
- Linux Linux: 75b54cb57ca34cbe7a87c6ac757c55360a624590 to < 386c86412608d3449006a318a662cbcd6ca1f668, 75b54cb57ca34cbe7a87c6ac757c55360a624590 to < 235b2115de892eab2e107a42efa7a4347baaa80b, 75b54cb57ca34cbe7a87c6ac757c55360a624590 to < 625af53a1564e31bb2df9adc3739df46137f46c1, 75b54cb57ca34cbe7a87c6ac757c55360a624590 to < 808a34cdbe8ce336c202d8ea6d5e48496764dc37
- Linux Linux: 4.9
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
In the Linux kernel, the following vulnerability has been resolved:
rxrpc: proc: size address buffers for %pISpc output
The AF_RXRPC procfs helpers format local and remote socket addresses into
fixed 50-byte stack buffers with "%pISpc".
That is too small for the longest current-tree IPv6-with-port form the
formatter can produce. In lib/vsprintf.c, the compressed IPv6 path uses a
dotted-quad tail not only for v4mapped addresses, but also for ISATAP
addresses via ipv6_addr_is_isatap().
As a result, a case such as
[ffff:ffff:ffff:ffff:0:5efe:255.255.255.255]:65535
is possible with the current formatter. That is 50 visible characters, so
51 bytes including the trailing NUL, which does not fit in the existing
char[50] buffers used by net/rxrpc/proc.c.
Size the buffers from the formatter's maximum textual form and switch the
call sites to scnprintf().
Changes since v1:
- correct the changelog to cite the actual maximum current-tree case
explicitly
- frame the proof around the ISATAP formatting path instead of the earlier
mapped-v4 example
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/386c86412608d3449006a318a662cbcd6ca1f668
- git.kernel.org/stable/c/235b2115de892eab2e107a42efa7a4347baaa80b
- git.kernel.org/stable/c/625af53a1564e31bb2df9adc3739df46137f46c1
- git.kernel.org/stable/c/808a34cdbe8ce336c202d8ea6d5e48496764dc37
- git.kernel.org/stable/c/a6042b8066b24dbcc7945616a157d4d43e463668
- git.kernel.org/stable/c/db297c78ce537c9ac96f0eda9b25ad72c8caefa9
- git.kernel.org/stable/c/10ebed83f9f6414af4e85bc85ffaeda7effdd874
- git.kernel.org/stable/c/a44ce6aa2efb61fe44f2cfab72bb01544bbca272
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON