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NVD / CVE Program· CNA CERT-PL

CVE-2026-11979: Stack-Based Buffer Overflow in libxml2

Noroxi assessment

Priority: Monitor (action score 7/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.14% (FIRST EPSS).
  • Someone with local access to the system can trigger it. No account or password is required. No special conditions are required; it is repeatable.
  • Fixed version: libxml2 (AlmaLinux:10) 2.12.5-10.el10_2.3; libxml2-devel (AlmaLinux:10) 2.12.5-10.el10_2.3; libxml2-static (AlmaLinux:10) 2.12.5-10.el10_2.3.

Low priority for now. Upgrade to libxml2 (AlmaLinux:10) 2.12.5-10.el10_2.3; libxml2-devel (AlmaLinux:10) 2.12.5-10.el10_2.3; libxml2-static (AlmaLinux:10) 2.12.5-10.el10_2.3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

libxml2 is vulnerable to multiple stack-based buffer overflows in the xmlcatalog utility when running in --shell mode. The usershell() function processes user input using fixed-size stack buffers without proper bounds checking. By supplying an overly long input line, an attacker can overflow internal buffers (command, arg, and argv) during input parsing. This results in memory corruption within the stack frame. Successful exploitation may cause a crash or potentially allow arbitrary code execution in the context of the xmlcatalog process. This issue has been fixed in the commit c2e233fc. NOTE: The maintainers of this project did not agree that this issue is a vulnerability and considered it a bug.

LowCVSS 1.8 · v4.0—No exploit Fix available
Published
Jun 29, 2026
Updated
Oct 25, 2026
EPSS
0.1% · 4th percentile

Report tools

JSON

Action score

7

Monitor

Low priority for now.

CVSS
7 / 40 · 1.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · CERT-PL
1.8
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:L/SI:L/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-11979

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
xmlsoftlibxml2

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • xmlsoft libxml2up to 2.15.3 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (CERT-PL). Independent of NVD's CPE analysis and usually ahead of it.

  • xmlsoft libxml2

    • up to and including 2.15.3affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10libxml2before 2.12.5-10.el10_2.32.12.5-10.el10_2.3
AlmaLinux:10libxml2-develbefore 2.12.5-10.el10_2.32.12.5-10.el10_2.3
AlmaLinux:10libxml2-staticbefore 2.12.5-10.el10_2.32.12.5-10.el10_2.3
AlmaLinux:10python3-libxml2before 2.12.5-10.el10_2.32.12.5-10.el10_2.3
AlmaLinux:8libxml2before 2.9.7-21.el8_10.72.9.7-21.el8_10.7
AlmaLinux:8libxml2-develbefore 2.9.7-21.el8_10.72.9.7-21.el8_10.7
AlmaLinux:8python3-libxml2before 2.9.7-21.el8_10.72.9.7-21.el8_10.7
AlmaLinux:9libxml2before 2.9.13-14.el9_8.42.9.13-14.el9_8.4
AlmaLinux:9libxml2-develbefore 2.9.13-14.el9_8.42.9.13-14.el9_8.4
AlmaLinux:9python3-libxml2before 2.9.13-14.el9_8.42.9.13-14.el9_8.4
Debian:12libxml2from 0—
Debian:14libxml2before 2.15.4+dfsg-12.15.4+dfsg-1
openSUSE:Leap 16.0libxml2before 2.13.8-160000.5.12.13.8-160000.5.1
openSUSE:Leap 16.0libxml2-pythonbefore 2.13.8-160000.5.12.13.8-160000.5.1
openSUSE:Tumbleweedlibxml2before 2.15.3-2.12.15.3-2.1
Red Hat:enterprise_linux:10.2libxml2before 0:2.12.5-10.el10_2.30:2.12.5-10.el10_2.3
Red Hat:enterprise_linux:10.2libxml2-debuginfobefore 0:2.12.5-10.el10_2.30:2.12.5-10.el10_2.3
Red Hat:enterprise_linux:10.2libxml2-debugsourcebefore 0:2.12.5-10.el10_2.30:2.12.5-10.el10_2.3
Red Hat:enterprise_linux:10.2libxml2-develbefore 0:2.12.5-10.el10_2.30:2.12.5-10.el10_2.3
Red Hat:enterprise_linux:10.2libxml2-staticbefore 0:2.12.5-10.el10_2.30:2.12.5-10.el10_2.3
Red Hat:enterprise_linux:10.2python3-libxml2before 0:2.12.5-10.el10_2.30:2.12.5-10.el10_2.3
Red Hat:enterprise_linux:10.2python3-libxml2-debuginfobefore 0:2.12.5-10.el10_2.30:2.12.5-10.el10_2.3
Red Hat:enterprise_linux:8::appstreamlibxml2-debuginfobefore 0:2.9.7-21.el8_10.70:2.9.7-21.el8_10.7
Red Hat:enterprise_linux:8::appstreamlibxml2-debugsourcebefore 0:2.9.7-21.el8_10.70:2.9.7-21.el8_10.7

+32

Same product

xmlsoft: all records

Other highest-scoring records for the same primary product.

  • CVE-2008-3529Heap-based buffer overflow in the xmlParseAttValueComplex function in parser.c in libxml2 before 2.7.0 allows context-dependent attackers to
    47Plan
  • CVE-2017-7376Buffer overflow in libxml2 allows remote attackers to execute arbitrary code by leveraging an incorrect limit for port values when handling
    46Plan
  • CVE-2022-40303An issue was discovered in libxml2 before 2.10.3.
    42Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-6732Apr 23, 2026 · Libxml2: libxml2: denial of service via crafted xsd-validated document
    30Monitor
  • ← EarlierCVE-2026-6653Jun 22, 2026 · libxml2: Use after free in xmlParseInternalSubset via improper entity resolution handling
    28Monitor
  • Later →CVE-2026-86137Sep 5, 2026 · In libxml2 before 2.15.4, xmlFAParsePosCharGroup has an out-of-bounds read, aka an out-of-bounds read in the NXT macro in xmlregexp.
    24Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
almalinux:libxml22.12.5-10.el10_2.3 · AlmaLinux:10Package registry (OSV)
almalinux:libxml2-devel2.12.5-10.el10_2.3 · AlmaLinux:10Package registry (OSV)
almalinux:libxml2-static2.12.5-10.el10_2.3 · AlmaLinux:10Package registry (OSV)
almalinux:python3-libxml22.12.5-10.el10_2.3 · AlmaLinux:10Package registry (OSV)
debian:libxml22.15.4+dfsg-1 · Debian:14Package registry (OSV)
opensuse:libxml22.15.3-2.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:libxml2-python2.13.8-160000.5.1 · openSUSE:Leap 16.0Package registry (OSV)
red hat:libxml20:2.15.3-0.1.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:libxml2-160:2.15.3-0.1.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:libxml2-debuginfo0:2.12.5-10.el10_2.3 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:libxml2-debugsource0:2.12.5-10.el10_2.3 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:libxml2-devel0:2.12.5-10.el10_2.3 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:libxml2-devel0:2.15.3-0.1.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:libxml2-static0:2.12.5-10.el10_2.3 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:libxml2-static0:2.15.3-0.1.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:python3-libxml20:2.12.5-10.el10_2.3 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:python3-libxml20:2.15.3-0.1.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:python3-libxml2-debuginfo0:2.12.5-10.el10_2.3 · Red Hat:enterprise_linux:10.2Package registry (OSV)
rocky linux:libxml20:2.12.5-10.el10_2.3 · Rocky Linux:10Package registry (OSV)
suse:libxml22.13.8-160000.5.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:libxml2-python2.13.8-160000.5.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:python-libxml22.9.4-46.102.2 · SUSE:Linux Enterprise Server 12 SP5-LTSSPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-8614068 days apartIn libxml2 before 2.15.4, xmlSnprintfElements in valid.c has a strcat stack-based buffer overflow.
    31Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • No account or password is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
A
Scope
X

Weakness class (CWE)

CWE-121 · Stack-based Buffer Overflow

CVSS vector

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records