CVE-2026-120831
Libslirp: libslirp: queue pointer corruption in if_output() leading to denial of service
A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm->m_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
6.5
Libslirp: libslirp: queue pointer corruption in if_output() leading to denial of service
A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm->m_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.
- Record
CVE-2026-120831- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-787
- Updated
- 2026-11-05
EUVDEUVD-2026-115656
6.5
A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm->m_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.
- Record
EUVD-2026-115656- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-05
GitHub AdvisoriesGHSA-c4qr-qpmh-whrf
6.5
A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the...
A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm->m_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.
- Record
GHSA-c4qr-qpmh-whrf- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-787
- Updated
- 2026-11-03
NVD
6.5
A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm->m_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.
- Record
CVE-2026-120831- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-787
- Updated
- 2026-11-05
OSV
6.5
Libslirp: libslirp: queue pointer corruption in if_output() leading to denial of service
A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm->m_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.
- Record
CVE-2026-120831- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-787
- Updated
- 2026-11-07
OSVDEBIAN-CVE-2026-120831
6.5
A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm->m_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.
- Record
DEBIAN-CVE-2026-120831- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-04
OSVUBUNTU-CVE-2026-120831
6.5
A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm->m_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.
- Record
UBUNTU-CVE-2026-120831- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-05
OSVAZL-112682 No score
CVE-2026-120831 affecting package libslirp 4.9.6-1
A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm->m_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.
- Record
AZL-112682- Updated
- 2026-11-05
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
libslirpAzure Linux:3 |
through 4.9.6-1 | None known |
libslirpDebian:12 |
All versions, plus listed versions 4.7.0-14.8.0-14.9.1-14.9.2-14.9.3-14.9.4-14.9.5-1 |
None known |
libslirpDebian:13 |
All versions, plus listed versions 4.8.0-14.8.0-1+deb13u14.9.1-14.9.2-14.9.3-14.9.4-14.9.5-1 |
None known |
libslirpDebian:14 |
All versions, plus listed versions 4.8.0-14.9.1-14.9.2-14.9.3-14.9.4-14.9.5-1 |
None known |
libslirpUbuntu:20.04:LTS |
All versions, plus listed versions 4.0.0-14.0.0-24.1.0-14.1.0-24.1.0-2ubuntu14.1.0-2ubuntu24.1.0-2ubuntu2.14.1.0-2ubuntu2.2 |
None known |
libslirpUbuntu:22.04:LTS |
All versions, plus listed versions 4.4.0-1build14.6.1-14.6.1-1build14.6.1-1ubuntu0.2 |
None known |
libslirpUbuntu:24.04:LTS |
All versions, plus listed versions 4.7.0-1ubuntu14.7.0-1ubuntu24.7.0-1ubuntu34.7.0-1ubuntu3.1 |
None known |
libslirpUbuntu:26.10 |
All versions, plus listed versions 4.9.1-1ubuntu14.9.3-1ubuntu1 |
None known |
libslirpUbuntu:26.04:LTS |
All versions, plus listed versions 4.8.0-1ubuntu14.9.1-1ubuntu14.9.1-1ubuntu1.1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, aliases, published, references | OSV | |
| affected, aliases, published, references | NVD, OSV | |
| facts | CVE List, EUVD | |
| affected, aliases, references | OSV | |
| references | OSV | |
| published | EUVD, NVD | |
| aliases | EUVD | |
| aliases, references | GitHub Advisories | |
| first indexed | CVE List |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-120831 is a medium vulnerability (CVSS 6.5) in Red Hat Enterprise Linux 10, published November 3, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.27%, the 18th percentile. No source names a fixed version.
References
access.redhat.com/security/cve/CVE-2026-120831
bugzilla.redhat.com/show_bug.cgi?id=2565425
gitlab.freedesktop.org/slirp/libslirp/-/commit/bad35bd3b529dc47aa109980a69a36da7848ab76
nvd.nist.gov/vuln/detail/CVE-2026-120831
github.com/advisories/GHSA-c4qr-qpmh-whrf
access.redhat.com/downloads/content/package-browser