CVE-2026-41401

MEDIUMNVD 6.56.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 6.5 from GitHub Security Advisory (severity: HIGH) published 2026-05-26. NVD baseline CVSS 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Elevated
6.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 6.5Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
45
EG Risk 45/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity65% × 45%
Impact severity (EG Severity): CVSS 6.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.6%
EPSS %ILE
49th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.5): severity, escalated by confirmed exploitation. This CVE's 6.5 is its impact severity (EG Severity), not escalated.

EG Severity
6.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

May 26, 2026

Last Modified

July 24, 2026

Advisory Details (4)

Auto-updated Jun 13, 2026
Patch available. Sources: github_commit, github.
GitHub advisoryMentions a patch (unverified)

Heap Use-After-Free write in libyang XML metadata parsing (lyd_parse_data_mem / lyd_parse_mem_xml) · Advisory · CESNET/libyang · GitHub

https://github.com/CESNET/libyang/security/advisories/GHSA-9f49-8x56-jmjc
Web page

libyang - Heap Use-After-Free Write in XML Metadata Parsing | Advisories | VulnCheck

https://www.vulncheck.com/advisories/libyang-heap-use-after-free-write-in-xml-metadata-parsing
GitHub commit Patch Available

commit 6b5ed47ee674 (CESNET/libyang)

Patch available: CESNET/libyang v5.4.9 (contains commit 6b5ed47ee674)

https://github.com/CESNET/libyang/commit/6b5ed47ee674fbe86b31bbebc4ff26889aeff38c

Vendor Advisories for CVE-2026-41401(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibyang3-tools (3.13.6-1ubuntu0.1) @ resolute2026-08-23ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
libyang1.0.225-1.1 ... 6.1.4-1 (29 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
libyang22.1.148-0.1, 2.1.148-0.2, 2.1.30-2, 2.1.30-2.1, 2.1.30-2.1~exp1
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
libyang3.12.2-1 ... 6.4.3-1 (23 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
libyang3.12.2-1 ... 6.4.3-1 (23 versions)
  • every version on: no fix on record
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 8× in last 7d / 29× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 274 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 174 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  2. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  3. 2026-10-18 03:41 UTCEG score recompute
  4. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  5. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  6. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  7. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  8. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  9. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  10. 2026-10-12 16:08 UTCEG score recompute
  11. 2026-10-11 19:50 UTCEG score recompute
  12. 2026-10-11 17:04 UTCEG score recompute
  13. 2026-10-11 14:30 UTCEG score recompute
  14. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  15. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  16. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  17. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  18. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  19. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  20. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  21. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  22. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  23. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  24. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  25. 2026-09-30 01:39 UTCOSV refresh
Show 75 more
  1. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  2. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  3. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  4. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  5. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  6. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  7. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  8. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  9. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  10. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  11. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  12. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  13. 2026-09-11 01:53 UTCOSV refresh
  14. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  15. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  16. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  17. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  18. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  19. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  20. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  21. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  22. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  23. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  24. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  25. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  26. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  27. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  28. 2026-08-23 16:21 UTCEG score recompute
  29. 2026-08-23 16:21 UTCVendor advisory
  30. 2026-08-23 16:21 UTCGHSA enrichmentGHSA-v7jp-vmx6-5429 · GitHub severity HIGH · GitHub CVSS 6.5
  31. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  32. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  33. 2026-08-21 21:28 UTCEG score recompute
  34. 2026-08-21 21:28 UTCVendor advisory
  35. 2026-08-21 21:28 UTCGHSA enrichmentGHSA-v7jp-vmx6-5429 · GitHub severity HIGH · GitHub CVSS 6.5
  36. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  37. 2026-08-20 18:15 UTCEG score recompute
  38. 2026-08-20 18:15 UTCVendor advisory
  39. 2026-08-20 18:15 UTCGHSA enrichmentGHSA-v7jp-vmx6-5429 · GitHub severity HIGH · GitHub CVSS 6.5
  40. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  41. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  42. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  43. 2026-08-17 09:33 UTCEG score recompute
  44. 2026-08-17 09:33 UTCVendor advisory
  45. 2026-08-17 09:33 UTCGHSA enrichmentGHSA-v7jp-vmx6-5429 · GitHub severity HIGH · GitHub CVSS 6.5
  46. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  47. 2026-08-16 03:06 UTCEG score recompute
  48. 2026-08-16 03:06 UTCVendor advisory
  49. 2026-08-16 03:06 UTCGHSA enrichmentGHSA-v7jp-vmx6-5429 · GitHub severity HIGH · GitHub CVSS 6.5
  50. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  51. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  52. 2026-08-15 00:59 UTCVendor advisory
  53. 2026-08-15 00:59 UTCGHSA enrichmentGHSA-v7jp-vmx6-5429 · GitHub severity HIGH · GitHub CVSS 6.5
  54. 2026-08-14 01:43 UTCEG score recompute
  55. 2026-08-14 01:43 UTCVendor advisory
  56. 2026-08-14 01:43 UTCGHSA enrichmentGHSA-v7jp-vmx6-5429 · GitHub severity HIGH · GitHub CVSS 6.5
  57. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  58. 2026-08-12 22:53 UTCEG score recompute
  59. 2026-08-12 22:53 UTCVendor advisory
  60. 2026-08-12 22:53 UTCGHSA enrichmentGHSA-v7jp-vmx6-5429 · GitHub severity HIGH · GitHub CVSS 6.5
  61. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  62. 2026-08-11 23:37 UTCEG score recompute
  63. 2026-08-11 23:37 UTCVendor advisory
  64. 2026-08-11 23:37 UTCGHSA enrichmentGHSA-v7jp-vmx6-5429 · GitHub severity HIGH · GitHub CVSS 6.5
  65. 2026-08-11 13:43 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  66. 2026-08-11 00:22 UTCEG score recompute
  67. 2026-08-11 00:22 UTCVendor advisory
  68. 2026-08-11 00:22 UTCGHSA enrichmentGHSA-v7jp-vmx6-5429 · GitHub severity HIGH · GitHub CVSS 6.5
  69. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  70. 2026-08-09 22:52 UTCEG score recompute
  71. 2026-08-09 22:52 UTCVendor advisory
  72. 2026-08-09 22:52 UTCGHSA enrichmentGHSA-v7jp-vmx6-5429 · GitHub severity HIGH · GitHub CVSS 6.5
  73. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  74. 2026-08-08 23:37 UTCEG score recompute
  75. 2026-08-08 23:37 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-41401?
CVE-2026-41401 is a medium-severity vulnerability; its CVE record was published on May 26, 2026. libyang before 5.2.6 contains a heap use-after-free write vulnerability in lydparsersetdataflags 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…
When was CVE-2026-41401 made public?
CVE-2026-41401 was made public on March 26, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on May 26, 2026. EchelonGraph's copy of the record carries a last-modified date of July 24, 2026; the record at its source may have been updated since.
Is CVE-2026-41401 actively exploited?
CVE-2026-41401 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (49th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-41401?
CVE-2026-41401 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-41401?
A fix for CVE-2026-41401 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-41401 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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