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CVE-2026-52917
sctp: diag: reject stale associations in dump_one path
Published 2026-06-24 (4 months ago) by the Linux kernel CNA. Subsystem net/sctp. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-52917 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixedDLA-4665-1 · 2026-07-03 · text | 6.1.176-1 | Update the kernel and reboot. DLA-4665-1 shipped the fix on 2026-07-03, in 6.1.176-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.94-1 | Update the kernel and reboot. Fixed in 6.12.94-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.0.13-1 | Update the kernel and reboot. Fixed in 7.0.13-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.13-1 | Update the kernel and reboot. Fixed in 7.0.13-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
The SCTP exact sock_diag lookup can hold a transport reference, block on lock_sock(sk), and then resume after sctp_association_free() has marked the association dead and freed its bind address list. When that happens, inet_assoc_attr_size() and inet_diag_msg_sctpasoc_fill() can still dereference association state that is no longer valid for reporting. In particular, inet_diag_msg_sctpasoc_fill() may read an empty bind-address list as a real sctp_sockaddr_entry and trigger an out-of-bounds read from unrelated association memory. Reject the association after taking the socket lock if it has been reaped or detached from the endpoint, and report the lookup as stale. This keeps the exact dump-one path from formatting torn association state.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
net/sctp/diag.c
- What this is
- SCTP PROTOCOLMAINTAINERS section matched on net/sctp/ · linux-sctp@vger.kernel.org · Maintained
- Kernel module
- sctp_diag
Check it on the machine
grep -wE 'CONFIG_INET_SCTP_DIAG|CONFIG_IP_SCTP' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w sctp_diagPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.
- bookworm, trixie, forky, sidm
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switches
- CONFIG_INET_SCTP_DIAG, CONFIG_IP_SCTP
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-06-24 (4 months ago)source
- CVSS
- 7.1 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.2% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/sctp
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 4.7 | 5.10.259 | 6657af827e21 |
| 4.7 | 5.15.210 | b2be72d40183 |
| 4.7 | 6.1.176 | 5425de8bd6e9 |
| 4.7 | 6.6.143 | e97c2a535e23 |
| 4.7 | 6.12.94 | 480f754580b5 |
| 4.7 | 6.18.36 | 78c4f964b2f9 |
| 4.7 | 7.0.13 | f5af203dec6e |
| 4.7 | 7.1 | 5eba3e48d78e |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4671-1 | 2026-07-05 | bullseye 6.1.176-1~deb11u1 | tracker |
| DLA-4665-1 | 2026-07-03 | bookworm 6.1.176-1 | tracker |
| DLA-4664-1 | 2026-07-03 | bullseye 5.10.259-1 | tracker |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The vulnerable path is reached through a local NETLINK_SOCK_DIAG SOCK_DIAG_BY_FAMILY exact SCTP diagnostic request, not directly by received SCTP packets. A remote peer may help create SCTP state, but the stale-state formatter is invoked by a local netlink caller.
- AC:LAttack complexity, low
- The race is between an exact diag lookup blocking on lock_sock() and association teardown, and a local attacker can create/tear down SCTP associations while issuing concurrent diag requests. Because the attacker controls both sides of the race, this is low complexity.
- PR:LPrivileges required, low
- NETLINK_SOCK_DIAG read requests are accepted from non-root users, and the SCTP diag path only uses CAP_NET_ADMIN to gate extra reporting details. The attacker needs only basic local unprivileged execution.
- UI:NUser interaction, none
- No victim action is required once the attacker can run local code. The attacker can create SCTP sockets, race teardown, and issue the diagnostic query directly.
- S:UScope, unchanged
- The issue affects kernel SCTP diagnostic handling within the same host kernel security authority. It does not cross a VM, IOMMU, or other separate security scope boundary.
- C:HConfidentiality impact, high
- The stale association can cause an out-of-bounds read from unrelated association memory and return data through the netlink diagnostic response. Following the higher-severity rule for kernel OOB reads, this is treated as high confidentiality impact.
- I:NIntegrity impact, none
- The investigated path formats and returns stale association state but does not write through attacker-controlled stale pointers. I found no direct modification primitive or control-flow corruption path.
- A:HAvailability impact, high
- The diag code continues dereferencing torn association and transport state after teardown, which can produce invalid stale-pointer reads and kernel oops conditions. Repeated local triggering can therefore cause high availability impact.