CVE-2025-15646

CRITICALPre-NVD 9.89.8
EchelonGraph scoreMEDIUM confidence

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

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-01. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: CISA-ADP (Vulnrichment) CVSS v3.1, EPSS, GitHub Security Advisory
Trending — 3 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

HTML::Gumbo versions before 0.19 for Perl disclose heap memory via type confusion.

Support for the element was added to libgumbo 0.10.0 in 2015, but the walk_tree function in lib/HTML/Gumbo.xs was not updated to support it. The element was treated as a text-node, where strlen() over-reads the heap block that the pointer addresses.

Any caller that runs parse() with the default format => 'string', or with format => 'tree', on input containing a element serializes the over-read bytes into the returned result, disclosing bounded heap contents. format => 'callback' reaches a croak on the unhandled node type and is unaffected.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
44
EG Risk 44/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity98% × 45%
The EG Score, 9.8 of 10.
Exploitation0.7% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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
0.7%
EPSS %ILE
50th
KEV
Not listed

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 none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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)14 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's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” 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

July 1, 2026

Last Modified

October 6, 2026

Advisory Details (4)

Auto-updated Oct 6, 2026
Patch available.
Web page

oss-security - CVE-2025-15646: HTML::Gumbo versions before 0.19 for Perl disclose heap memory via type confusion

http://www.openwall.com/lists/oss-security/2026/07/01/7
Web pageMentions a patch (unverified)

#1104789 - libhtml-gumbo-perl: erratic behavior on the unsupported template HTML element - GUMBO_NODE_TEMPLATE node type (CVE-2025-15646) - Debian Bug report logs

https://bugs.debian.org/1104789

Vendor Advisories for CVE-2025-15646(1)

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

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
libhtml-gumbo-perl0.18-2 ... 0.20-1 (6 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
libhtml-gumbo-perl0.18-3
  • every version up to 0.18-3+deb12u1: fixed in 0.18-3+deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
libhtml-gumbo-perl—
  • every version up to 0.18-5: fixed in 0.18-5
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
libhtml-gumbo-perl—
  • every version up to 0.18-5: fixed in 0.18-5
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 45× 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 98 of 424 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. 2 repeat rows among the latest 100 are merged into the row they repeat. The 326 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-11 20:53 UTCEG score recompute
  2. 2026-10-11 19:03 UTCEG score recompute
  3. 2026-10-11 15:43 UTCEG score recompute
  4. 2026-10-11 13:46 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  5. 2026-10-10 19:58 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  6. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  7. 2026-10-08 17:08 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  8. 2026-10-07 23:46 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  9. 2026-10-06 22:12 UTCEG score recompute
  10. 2026-10-06 22:12 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-10-06 15:16 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  12. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  13. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  14. 2026-10-03 14:24 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  15. 2026-10-01 19:48 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  16. 2026-09-30 21:30 UTCEG score recompute
  17. 2026-09-30 21:30 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  18. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  19. 2026-09-28 13:50 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  20. 2026-09-26 15:57 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  21. 2026-09-24 14:02 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  22. 2026-09-23 13:46 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  23. 2026-09-23 11:14 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  24. 2026-09-23 06:53 UTCEG score recompute
  25. 2026-09-23 06:53 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
Show 73 more
  1. 2026-09-22 14:47 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  2. 2026-09-20 20:14 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  3. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  4. 2026-09-18 10:27 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  5. 2026-09-18 06:35 UTCEG score recompute
  6. 2026-09-18 06:35 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  7. 2026-09-16 14:06 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  8. 2026-09-16 05:13 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  9. 2026-09-15 03:08 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  10. 2026-09-14 08:14 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-09-14 04:15 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-09-14 00:23 UTCEG score recompute
  13. 2026-09-14 00:23 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  14. 2026-09-13 16:45 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  15. 2026-09-13 13:00 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  16. 2026-09-13 09:09 UTCEG score recompute
  17. 2026-09-13 09:09 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  18. 2026-09-12 14:59 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  19. 2026-09-12 14:46 UTCEG score recompute
  20. 2026-09-12 14:46 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-09-11 14:51 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  22. 2026-09-11 09:35 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  23. 2026-09-10 09:33 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  24. 2026-09-08 21:59 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  25. 2026-09-07 16:00 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  26. 2026-09-06 14:27 UTCEG score recompute
  27. 2026-09-06 14:27 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  28. 2026-09-06 13:46 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  29. 2026-09-06 02:25 UTCEG score recompute
  30. 2026-09-06 02:25 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  31. 2026-09-04 13:59 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  32. 2026-09-04 05:05 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  33. 2026-09-02 14:10 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  34. 2026-09-01 13:52 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  35. 2026-09-01 04:38 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  36. 2026-08-31 00:56 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  37. 2026-08-30 21:05 UTCEG score recompute
  38. 2026-08-30 21:05 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  39. 2026-08-30 19:16 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  40. 2026-08-30 17:10 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  41. 2026-08-30 13:10 UTCEG score recompute
  42. 2026-08-30 13:10 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  43. 2026-08-30 01:21 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  44. 2026-08-28 21:40 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  45. 2026-08-28 02:47 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  46. 2026-08-27 22:27 UTCEG score recompute
  47. 2026-08-27 22:27 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  48. 2026-08-27 14:24 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  49. 2026-08-26 14:45 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  50. 2026-08-25 13:47 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  51. 2026-08-25 04:45 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  52. 2026-08-25 00:53 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  53. 2026-08-24 21:02 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  54. 2026-08-24 14:46 UTCEG score recompute
  55. 2026-08-24 14:46 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  56. 2026-08-24 14:15 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  57. 2026-08-24 10:54 UTCEG score recompute
  58. 2026-08-24 10:54 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  59. 2026-08-24 04:11 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  60. 2026-08-23 23:07 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  61. 2026-08-23 19:15 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  62. 2026-08-23 15:22 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  63. 2026-08-23 11:30 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  64. 2026-08-23 07:38 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  65. 2026-08-23 03:47 UTCEG score recompute
  66. 2026-08-23 03:47 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  67. 2026-08-23 00:18 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  68. 2026-08-22 23:55 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  69. 2026-08-22 20:03 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  70. 2026-08-22 15:05 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  71. 2026-08-22 11:12 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  72. 2026-08-22 07:20 UTCGHSA enrichmentGHSA-754r-h5mg-r795 · GitHub severity CRITICAL · GitHub CVSS 9.8
  73. 2026-08-22 01:02 UTCEG score recompute

Frequently asked(5)

What is CVE-2025-15646?
CVE-2025-15646 is a critical-severity vulnerability; its CVE record was published on July 1, 2026. HTML::Gumbo versions before 0.19 for Perl disclose heap memory via type confusion. Support for the <template> element was added to libgumbo 0.10.0 in 2015, but the walk_tree function in lib/HTML/Gumbo.xs was not updated to support it. The element was treated as a text-node, where strlen()…
When was the CVE record for CVE-2025-15646 published?
The CVE record for CVE-2025-15646 was published on July 1, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 6, 2026; the record at its source may have been updated since.
Is CVE-2025-15646 actively exploited?
CVE-2025-15646 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (50th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2025-15646?
CVE-2025-15646 has a CVSS v3.1 base score of 9.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2025-15646?
A fix for CVE-2025-15646 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2025-15646 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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