CVE-2026-120830
Libslirp: libslirp: out-of-bounds heap read in icmp_forward_error() leading to information disclosure
A flaw was found in libslirp in icmp_forward_error(). When building an ICMP error response, the length of the quoted original IPv4 packet was taken from the IP header without clamping it to the actual buffer length. A truncated or malformed packet could cause an out-of-bounds heap read, leaking host memory into the ICMP error packet returned to a guest or container.
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
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
7.4
Libslirp: libslirp: out-of-bounds heap read in icmp_forward_error() leading to information disclosure
A flaw was found in libslirp in icmp_forward_error(). When building an ICMP error response, the length of the quoted original IPv4 packet was taken from the IP header without clamping it to the actual buffer length. A truncated or malformed packet could cause an out-of-bounds heap read, leaking host memory into the ICMP error packet returned to a guest or container.
- Record
CVE-2026-120830- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Weakness
- CWE-125
- Updated
- 2026-11-04
EUVDEUVD-2026-115651
7.4
A flaw was found in libslirp in icmp_forward_error(). When building an ICMP error response, the length of the quoted original IPv4 packet was taken from the IP header without clamping it to the actual buffer length. A truncated or malformed packet could cause an out-of-bounds heap read, leaking host memory into the ICMP error packet returned to a guest or container.
- Record
EUVD-2026-115651- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Updated
- 2026-11-04
GitHub AdvisoriesGHSA-r5f9-pc8m-f599
7.4
A flaw was found in libslirp in icmp_forward_error(). When building an ICMP error response, the...
A flaw was found in libslirp in icmp_forward_error(). When building an ICMP error response, the length of the quoted original IPv4 packet was taken from the IP header without clamping it to the actual buffer length. A truncated or malformed packet could cause an out-of-bounds heap read, leaking host memory into the ICMP error packet returned to a guest or container.
- Record
GHSA-r5f9-pc8m-f599- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Weakness
- CWE-125
- Updated
- 2026-11-03
NVD
7.4
A flaw was found in libslirp in icmp_forward_error(). When building an ICMP error response, the length of the quoted original IPv4 packet was taken from the IP header without clamping it to the actual buffer length. A truncated or malformed packet could cause an out-of-bounds heap read, leaking host memory into the ICMP error packet returned to a guest or container.
- Record
CVE-2026-120830- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Weakness
- CWE-125
- Updated
- 2026-11-04
OSV
7.4
Libslirp: libslirp: out-of-bounds heap read in icmp_forward_error() leading to information disclosure
A flaw was found in libslirp in icmp_forward_error(). When building an ICMP error response, the length of the quoted original IPv4 packet was taken from the IP header without clamping it to the actual buffer length. A truncated or malformed packet could cause an out-of-bounds heap read, leaking host memory into the ICMP error packet returned to a guest or container.
- Record
CVE-2026-120830- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Weakness
- CWE-125
- Updated
- 2026-11-06
OSVDEBIAN-CVE-2026-120830
7.4
A flaw was found in libslirp in icmp_forward_error(). When building an ICMP error response, the length of the quoted original IPv4 packet was taken from the IP header without clamping it to the actual buffer length. A truncated or malformed packet could cause an out-of-bounds heap read, leaking host memory into the ICMP error packet returned to a guest or container.
- Record
DEBIAN-CVE-2026-120830- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Updated
- 2026-11-05
OSVUBUNTU-CVE-2026-120830
7.4
A flaw was found in libslirp in icmp_forward_error(). When building an ICMP error response, the length of the quoted original IPv4 packet was taken from the IP header without clamping it to the actual buffer length. A truncated or malformed packet could cause an out-of-bounds heap read, leaking host memory into the ICMP error packet returned to a guest or container.
- Record
UBUNTU-CVE-2026-120830- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Updated
- 2026-11-05
OSVAZL-112679 No score
CVE-2026-120830 affecting package libslirp 4.9.6-1
A flaw was found in libslirp in icmp_forward_error(). When building an ICMP error response, the length of the quoted original IPv4 packet was taken from the IP header without clamping it to the actual buffer length. A truncated or malformed packet could cause an out-of-bounds heap read, leaking host memory into the ICMP error packet returned to a guest or container.
- Record
AZL-112679- 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 | CVE List, EUVD, NVD, OSV | |
| affected, aliases, published, references | OSV | |
| facts | OSV | |
| affected, aliases, references | OSV | |
| references | NVD, OSV | |
| aliases, published | EUVD | |
| products, published, references, severity, title | CVE List | |
| first indexed | GitHub Advisories |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-120830 is a high vulnerability (CVSS 7.4) 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 0.22%, the 12th percentile. No source names a fixed version.
References
access.redhat.com/security/cve/CVE-2026-120830
bugzilla.redhat.com/show_bug.cgi?id=2565424
gitlab.freedesktop.org/slirp/libslirp/-/commit/21b33a6c5588af9f58d15e528fdc1019452708e4
nvd.nist.gov/vuln/detail/CVE-2026-120830
github.com/advisories/GHSA-r5f9-pc8m-f599
access.redhat.com/downloads/content/package-browser