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CVE-2026-41401

libyang - Heap Use-After-Free Write in XML Metadata Parsing

6.9 MediumFix available

libyang before 5.4.3 contains a heap use-after-free write vulnerability in lyd_parser_set_data_flags that incorrectly updates metadata list pointers when freeing non-head default metadata entries. Attackers can trigger this vulnerability by submitting crafted YANG XML documents with specific metadata attributes to applications parsing untrusted XML data, causing process crashes or potential code execution.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.67%Up 0.6 points since May 27, 2026
90%50%10%1%

What each source reports

CVE List Score used 6.9

libyang - Heap Use-After-Free Write in XML Metadata Parsing

libyang before 5.4.3 contains a heap use-after-free write vulnerability in lyd_parser_set_data_flags that incorrectly updates metadata list pointers when freeing non-head default metadata entries. Attackers can trigger this vulnerability by submitting crafted YANG XML documents with specific metadata attributes to applications parsing untrusted XML data, causing process crashes or potential code execution.

Record
CVE-2026-41401
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-416
Updated
2026-11-02
EUVDEUVD-2026-31832 6.9

libyang before 5.4.3 contains a heap use-after-free write vulnerability in lyd_parser_set_data_flags that incorrectly updates metadata list pointers when freeing non-head default metadata entries. Attackers can trigger this vulnerability by submitting crafted YANG XML documents with specific metadata attributes to applications parsing untrusted XML data, causing process crashes or potential code execution.

Record
EUVD-2026-31832
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-v7jp-vmx6-5429 7.1

libyang before 5.2.6 contains a heap use-after-free write vulnerability in...

libyang before 5.2.6 contains a heap use-after-free write vulnerability in lyd_parser_set_data_flags that incorrectly updates metadata list pointers when freeing non-head default metadata entries. Attackers can trigger this vulnerability by submitting crafted YANG XML documents with specific metadata attributes to applications parsing untrusted XML data, causing process crashes or potential code execution.

Record
GHSA-v7jp-vmx6-5429
CVSS 4.0
7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/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
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-416
Updated
2026-11-02
NVD 7.1

libyang before 5.4.3 contains a heap use-after-free write vulnerability in lyd_parser_set_data_flags that incorrectly updates metadata list pointers when freeing non-head default metadata entries. Attackers can trigger this vulnerability by submitting crafted YANG XML documents with specific metadata attributes to applications parsing untrusted XML data, causing process crashes or potential code execution.

Record
CVE-2026-41401
CVSS 4.0
7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/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
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-416
Updated
2026-11-02
OSV 7.1

libyang - Heap Use-After-Free Write in XML Metadata Parsing

libyang before 5.4.3 contains a heap use-after-free write vulnerability in lyd_parser_set_data_flags that incorrectly updates metadata list pointers when freeing non-head default metadata entries. Attackers can trigger this vulnerability by submitting crafted YANG XML documents with specific metadata attributes to applications parsing untrusted XML data, causing process crashes or potential code execution.

Record
CVE-2026-41401
CVSS 4.0
7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness
CWE-416
Updated
2026-11-02
OSVDEBIAN-CVE-2026-41401 7.1

libyang before 5.4.3 contains a heap use-after-free write vulnerability in lyd_parser_set_data_flags that incorrectly updates metadata list pointers when freeing non-head default metadata entries. Attackers can trigger this vulnerability by submitting crafted YANG XML documents with specific metadata attributes to applications parsing untrusted XML data, causing process crashes or potential code execution.

Record
DEBIAN-CVE-2026-41401
CVSS 4.0
7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/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
Updated
2026-11-02
Show 11 moreShow less
OSVUBUNTU-CVE-2026-41401 7.1

libyang before 5.4.3 contains a heap use-after-free write vulnerability in lyd_parser_set_data_flags that incorrectly updates metadata list pointers when freeing non-head default metadata entries. Attackers can trigger this vulnerability by submitting crafted YANG XML documents with specific metadata attributes to applications parsing untrusted XML data, causing process crashes or potential code execution.

Record
UBUNTU-CVE-2026-41401
CVSS 4.0
7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-05
OSVAZL-87354 No score

CVE-2026-41401 affecting package libyang for versions less than 2.1.148-3

libyang before 5.4.3 contains a heap use-after-free write vulnerability in lyd_parser_set_data_flags that incorrectly updates metadata list pointers when freeing non-head default metadata entries. Attackers can trigger this vulnerability by submitting crafted YANG XML documents with specific metadata attributes to applications parsing untrusted XML data, causing process crashes or potential code execution.

Record
AZL-87354
Updated
2026-11-05
OSVMGASA-2026-0302 No score

Updated libyang packages fix a security vulnerability

The updated packages fix a security vulnerability: Heap Use-After-Free Write in XML Metadata Parsing. (CVE-2026-41401)

Record
MGASA-2026-0302
Updated
2026-11-02
OSVopenSUSE-SU-2026:10868-1 No score

libyang-devel-3.13.6-2.1 on GA media

These are all security issues fixed in the libyang-devel-3.13.6-2.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:10868-1
Updated
2026-11-02
OSVopenSUSE-SU-2026:21113-1 No score

Security update for libyang

This update for libyang fixes the following issues

  • CVE-2026-41401: use-after-free in lyd_parser_set_data_flags when processing crafted YANG XML documents with specific metadata attributes (bsc#1266316).
  • CVE-2026-44673: integer overflow in lyb_read_string() of src/parser_lyb.c leads to heap buffer overflow when parsing a maliciously crafted LYB binary blob (bsc#1265330).
Record
openSUSE-SU-2026:21113-1
Updated
2026-11-02
OSVSUSE-SU-2026:22200-1 No score

Security update for libyang

This update for libyang fixes the following issues

  • CVE-2026-41401: use-after-free in lyd_parser_set_data_flags when processing crafted YANG XML documents with specific metadata attributes (bsc#1266316).
  • CVE-2026-44673: integer overflow in lyb_read_string() of src/parser_lyb.c leads to heap buffer overflow when parsing a maliciously crafted LYB binary blob (bsc#1265330).
Record
SUSE-SU-2026:22200-1
Updated
2026-11-02
OSVSUSE-SU-2026:22208-1 No score

Security update for libyang

This update for libyang fixes the following issues

  • CVE-2026-41401: use-after-free in lyd_parser_set_data_flags when processing crafted YANG XML documents with specific metadata attributes (bsc#1266316).
  • CVE-2026-44673: integer overflow in lyb_read_string() of src/parser_lyb.c leads to heap buffer overflow when parsing a maliciously crafted LYB binary blob (bsc#1265330).
Record
SUSE-SU-2026:22208-1
Updated
2026-11-02
OSVSUSE-SU-2026:2334-1 No score

Security update for libyang

This update for libyang fixes the following issues

  • CVE-2026-41401: use-after-free in lyd_parser_set_data_flags when processing crafted YANG XML documents with specific metadata attributes (bsc#1266316).
  • CVE-2026-44673: integer overflow in lyb_read_string() of src/parser_lyb.c leads to heap buffer overflow when parsing a maliciously crafted LYB binary blob (bsc#1265330).
Record
SUSE-SU-2026:2334-1
Updated
2026-11-02
OSVSUSE-SU-2026:2335-1 No score

Security update for libyang

This update for libyang fixes the following issues

  • CVE-2026-41401: use-after-free in lyd_parser_set_data_flags when processing crafted YANG XML documents with specific metadata attributes (bsc#1266316).
  • CVE-2026-44673: integer overflow in lyb_read_string() of src/parser_lyb.c leads to heap buffer overflow when parsing a maliciously crafted LYB binary blob (bsc#1265330).
Record
SUSE-SU-2026:2335-1
Updated
2026-11-02
OSVSUSE-SU-2026:2337-1 No score

Security update for libyang

This update for libyang fixes the following issues

  • CVE-2026-41401: use-after-free in lyd_parser_set_data_flags when processing crafted YANG XML documents with specific metadata attributes (bsc#1266316).
  • CVE-2026-44673: integer overflow in lyb_read_string() of src/parser_lyb.c leads to heap buffer overflow when parsing a maliciously crafted LYB binary blob (bsc#1265330).
Record
SUSE-SU-2026:2337-1
Updated
2026-11-02
OSVUSN-8485-1 No score

libyang vulnerability

It was discovered that libyang incorrectly handled certain metadata list pointers. An attacker could use this issue to cause libyang to crash, resulting in a denial of service, or possibly execute arbitrary code.

Record
USN-8485-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
libyang
Azure Linux:3
 before 2.1.148-3
2.1.148-3
libyang
Debian:13
 All versions, plus listed versions
3.12.2-13.13.5-13.13.5-23.13.6-13.13.6-1~bpo13+1
Show 20 moreShow less
4.2.2-14.2.2-24.2.2-34.3.3-14.3.4-14.7.3-15.0.2-15.0.8-15.4.1+really5.4.1-15.4.1-15.4.5-15.4.9-15.7.1-15.8.5-15.8.6-15.8.6-26.1.4-16.4.13-16.4.3-16.4.6-1
 None known
libyang
Debian:14
 before 6.4.13-1, plus listed versions
3.12.2-13.13.5-13.13.5-23.13.6-13.13.6-1~bpo13+1
Show 19 moreShow less
4.2.2-14.2.2-24.2.2-34.3.3-14.3.4-14.7.3-15.0.2-15.0.8-15.4.1+really5.4.1-15.4.1-15.4.5-15.4.9-15.7.1-15.8.5-15.8.6-15.8.6-26.1.4-16.4.3-16.4.6-1
6.4.13-1
libyang2
Debian:12
 All versions, plus listed versions
2.1.148-0.12.1.148-0.22.1.30-22.1.30-2.12.1.30-2.1~exp1
 None known
libyang
Mageia:10
 before 3.13.5-1.1.mga10
3.13.5-1.1.mga10
libyang
SUSE:Linux Enterprise Server 16.0
From an advisory covering 2 CVEs
 before 2.1.148-160000.4.1
2.1.148-160000.4.1
libyang
SUSE:Linux Enterprise Server for SAP applications 16.0
From an advisory covering 2 CVEs
 before 2.1.148-160000.4.1
2.1.148-160000.4.1
libyang
SUSE:Linux Enterprise Server 12 SP5-LTSS
From an advisory covering 2 CVEs
 before 2.1.148-8.8.1
2.1.148-8.8.1
libyang
SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5
From an advisory covering 2 CVEs
 before 2.1.148-8.8.1
2.1.148-8.8.1
libyang
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS
From an advisory covering 2 CVEs
 before 2.1.55-150500.3.5.1
2.1.55-150500.3.5.1
Show 12 moreShow less
Affected packages
PackageAffectedFixed
libyang
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS
From an advisory covering 2 CVEs
 before 2.1.55-150500.3.5.1
2.1.55-150500.3.5.1
libyang
SUSE:Linux Enterprise Server 15 SP5-LTSS
From an advisory covering 2 CVEs
 before 2.1.55-150500.3.5.1
2.1.55-150500.3.5.1
libyang
SUSE:Linux Enterprise Server 15 SP6-LTSS
From an advisory covering 2 CVEs
 before 2.1.55-150500.3.5.1
2.1.55-150500.3.5.1
libyang
SUSE:Linux Enterprise Server for SAP Applications 15 SP5
From an advisory covering 2 CVEs
 before 2.1.55-150500.3.5.1
2.1.55-150500.3.5.1
libyang
SUSE:Linux Enterprise Server for SAP Applications 15 SP6
From an advisory covering 2 CVEs
 before 2.1.55-150500.3.5.1
2.1.55-150500.3.5.1
libyang
SUSE:Linux Enterprise Module for Server Applications 15 SP7
From an advisory covering 2 CVEs
 before 2.1.148-150700.3.5.1
2.1.148-150700.3.5.1
libyang
Ubuntu:20.04:LTS
 All versions, plus listed versions
0.16.105-10.16.105-20.16.105-30.16.105-3build1
 None known
libyang
Ubuntu:22.04:LTS
 All versions, plus listed versions
1.0.225-1.1
 None known
libyang
Ubuntu:25.10
 before 3.13.5-2ubuntu0.1, plus listed versions
3.7.8-33.12.2-13.12.2-1ubuntu13.13.5-2
3.13.5-2ubuntu0.1
libyang
Ubuntu:26.04:LTS
 before 3.13.6-1ubuntu0.1, plus listed versions
3.13.5-23.13.6-1
3.13.6-1ubuntu0.1
libyang
openSUSE:Tumbleweed
 before 3.13.6-2.1
3.13.6-2.1
libyang
openSUSE:Leap 16.0
From an advisory covering 2 CVEs
 before 2.1.148-160000.4.1
2.1.148-160000.4.1

History

History
RecordedChangedSources
affected
factsOSV
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-41401 is a medium vulnerability (CVSS 6.9) in Cesnet Libyang, published May 26, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.67%, the 52nd percentile. Fixed in libyang 2.1.148-3.

References

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