CVE-2026-5121 | Libarchive: libarchive: arbitrary code execution via integer overflow in iso9660 image processing

A flaw was found in libarchive. On 32-bit systems, an integer overflow vulnerability exists in the zisofs block pointer allocation logic. A remote attacker can exploit this by providing a specially crafted ISO9660 image, which can lead to a heap buffer overflow. This could potentially allow for arbitrary code execution on the affected system.

Published: 2026-03-30 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-5121 is rated Moderate Risk (52.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.07%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-5121

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.09% 1.07% +0.99%
2 2026-04-15 0.18% 0.09% -0.10%
3 2026-04-01 0.18%

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-5121

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
3.9 3.6 [email protected]
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-5121

GitHub Security Advisory for CVE-2026-5121

GHSA-2vwv-vqpv-v8vc · Severity: critical — A flaw was found in libarchive. On 32-bit systems, an integer overflow vulnerability exists in...

OS Trackers for CVE-2026-5121

vendor priority summary link
debian not yet assigned CVE-2026-5121 not yet assigned priority: Debian including 1 source packages (libarchive), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-5121
redhat medium https://access.redhat.com/security/cve/CVE-2026-5121
suse high CVE-2026-5121 severity important: SUSE including 7 source package names (bsdtar-3.3.3-7.el8_10, bsdtar-3.5.3-9.el9_7, …), 9 product×package rows across 5 product lines (SUSE Liberty Linux 8, SUSE Liberty Linux 9, … (5 product lines)): Fixed 6, Known Not Affected 3. https://www.suse.com/security/cve/CVE-2026-5121/
ubuntu medium CVE-2026-5121 medium priority: Ubuntu including 1 source packages (libarchive), 9 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): needed 8, needs-triage 1. https://ubuntu.com/security/CVE-2026-5121

Affected software / configurations for CVE-2026-5121

Vendor Product Version Raw CPE
libarchive libarchive cpe:2.3:a:libarchive:libarchive:-:*:*:*:*:*:*:*
redhat hardened_images cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:*
redhat openshift_container_platform 4.0 cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*
redhat enterprise_linux 6.0 cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*
redhat enterprise_linux 7.0 cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux 9.0 cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
redhat enterprise_linux 10.0 cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*

References for CVE-2026-5121

URL Tags
https://access.redhat.com/errata/RHSA-2026:10065
https://access.redhat.com/errata/RHSA-2026:10097
https://access.redhat.com/errata/RHSA-2026:11768
https://access.redhat.com/errata/RHSA-2026:12071
https://access.redhat.com/errata/RHSA-2026:12274
https://access.redhat.com/errata/RHSA-2026:13812
https://access.redhat.com/errata/RHSA-2026:14773
https://access.redhat.com/errata/RHSA-2026:14937
https://access.redhat.com/errata/RHSA-2026:15087
https://access.redhat.com/errata/RHSA-2026:16008
https://access.redhat.com/errata/RHSA-2026:16009
https://access.redhat.com/errata/RHSA-2026:16030
https://access.redhat.com/errata/RHSA-2026:16174
https://access.redhat.com/errata/RHSA-2026:17596
https://access.redhat.com/errata/RHSA-2026:19724
https://access.redhat.com/errata/RHSA-2026:19725
https://access.redhat.com/errata/RHSA-2026:20040
https://access.redhat.com/errata/RHSA-2026:21690
https://access.redhat.com/errata/RHSA-2026:25096
https://access.redhat.com/errata/RHSA-2026:8510
https://access.redhat.com/errata/RHSA-2026:8517
https://access.redhat.com/errata/RHSA-2026:8521
https://access.redhat.com/errata/RHSA-2026:8534
https://access.redhat.com/errata/RHSA-2026:8864
https://access.redhat.com/errata/RHSA-2026:8866
https://access.redhat.com/errata/RHSA-2026:8867
https://access.redhat.com/errata/RHSA-2026:8873
https://access.redhat.com/errata/RHSA-2026:8908
https://access.redhat.com/errata/RHSA-2026:8944
https://access.redhat.com/errata/RHSA-2026:9026
https://access.redhat.com/errata/RHSA-2026:9592
https://access.redhat.com/errata/RHSA-2026:9832
https://access.redhat.com/security/cve/CVE-2026-5121 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2452945
https://github.com/advisories/GHSA-2vwv-vqpv-v8vc Third Party Advisory
https://github.com/libarchive/libarchive/pull/2934 Issue Tracking Patch
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