ncsi.c in libslirp through 4.3.1 has a buffer over-read because it tries to read a…
Priority LOW 23CWE-125Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Partial Red Hat: 2 fixed, 4 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-125 and the CVSS impact.
Summary
ncsi.c in libslirp through 4.3.1 has a buffer over-read because it tries to read a certain amount of header data even if that exceeds the total packet length.
Why it matters now
EPSS 0.0146 73rd percentileScored 2026-11-07
Fix Partial Red Hat: 1 advisoryRed Hat: 2 fixed, 4 without a fix
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 4
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:libslirp_project:libslirp:*:*:*:*:*:*:*:* | up to 4.3.1 | Vulnerable | Libslirp Project |
| cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* | 32 | Vulnerable | Fedoraproject |
| cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* | 33 | Vulnerable | Fedoraproject |
| cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* | 10.0 | Vulnerable | Debian |
- cpe:2.3:a:libslirp_project:libslirp:*:*:*:*:*:*:*:* Versions up to 4.3.1 Vulnerable ·Libslirp Project
- cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* Versions 32 Vulnerable ·Fedoraproject
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
- cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian
Remediation
Red Hat 1 advisory
- RHSA-2021:1762 Released 2021-05-18 · Red Hat rating Moderatevirt:rhel and virt-devel:rhel security, bug fix, and enhancement update
- Red Hat CodeReady Linux Builder (v. 8) SLOF-20191022-3.git899d9883.module+el8.3.0+6423+e4cb6418.src::virt-devel:rhel, hivex-1.3.18-20.module+el8.3.0+6423+e4cb6418.i686::virt-devel:rhel, hivex-devel-1.3.18-20.module+el8.3.0+6423+e4cb6418.i686::virt-devel:rhel +47
- Red Hat Enterprise Linux AppStream (v. 8) SLOF-20191022-3.git899d9883.module+el8.3.0+6423+e4cb6418.noarch::virt:rhel, SLOF-20191022-3.git899d9883.module+el8.3.0+6423+e4cb6418.src::virt:rhel, hivex-1.3.18-20.module+el8.3.0+6423+e4cb6418.aarch64::virt:rhel +47
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 5 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 Advanced Virtualization | Affected | No fix yet |
| Red Hat CodeReady Linux Builder (v. 8) | Fixed | RHSA-2021:1762 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2021:1762 |
Not affected: 1 product
- Red Hat Enterprise Linux 5
Timeline
- 2026-10-02 Threatist record created from CVE-2020-29129
References
Advisory 5
- https://lists.freedesktop.org/archives/slirp/2020-November/000115.html
- [oss-security] 20201127 CVE-2020-29129 CVE-2020-29130 QEMU: slirp: out-of-bounds access while processing ARP/NCSI packets
- FEDORA-2020-77f93f41be
- FEDORA-2020-331e1318dd
- [debian-lts-announce] 20220905 [SECURITY] [DLA 3099-1] qemu security update
Sources
- CVE-2020-29129 · CVE Program
- CVE-2020-29129 · NVD
- FIRST EPSS
- CVE-2020-29129 · Red Hat security data · CC BY 4.0
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