High severity · published Apr 24, 2026
CVE-2026-31630
rxrpc: proc: size address buffers for %pISpc output
7.8
CVSS
0.2%
EPSS
No
On KEV
Description
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
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 7% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
4.9.1 before 6.18.23; 6.19 before 6.19.13; 4.9; 7.0; 7.0; 7.0; +4 more · source: NVD
LI
Linux · Linux
75b54cb57ca34cbe7a87c6ac757c55360a624590 before 386c86412608d3449006a318a662cbcd6ca1f668; 75b54cb57ca34cbe7a87c6ac757c55360a624590 before 235b2115de892eab2e107a42efa7a4347baaa80b; 75b54cb57ca34cbe7a87c6ac757c55360a624590 before 625af53a1564e31bb2df9adc3739df46137f46c1; 75b54cb57ca34cbe7a87c6ac757c55360a624590 before 808a34cdbe8ce336c202d8ea6d5e48496764dc37; 75b54cb57ca34cbe7a87c6ac757c55360a624590 before a6042b8066b24dbcc7945616a157d4d43e463668; 75b54cb57ca34cbe7a87c6ac757c55360a624590 before db297c78ce537c9ac96f0eda9b25ad72c8caefa9; +3 more · source: vendor
SS
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem · Siemens
0 · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-31630
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-31630
Patch
https://git.kernel.org/stable/c/10ebed83f9f6414af4e85bc85ffaeda7effdd874
git.kernel.org
https://git.kernel.org/stable/c/235b2115de892eab2e107a42efa7a4347baaa80b
git.kernel.org
https://git.kernel.org/stable/c/386c86412608d3449006a318a662cbcd6ca1f668
git.kernel.org
https://git.kernel.org/stable/c/625af53a1564e31bb2df9adc3739df46137f46c1
git.kernel.org
https://git.kernel.org/stable/c/808a34cdbe8ce336c202d8ea6d5e48496764dc37
Patch
https://git.kernel.org/stable/c/a44ce6aa2efb61fe44f2cfab72bb01544bbca272
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