CVE-2026-77643

MEDIUMPre-NVD 4.44.4—
EchelonGraph scoreMEDIUM confidence

Score 4.4 from GitHub Security Advisory published 2026-08-21. A secondary CVSS source baseline 4.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
4.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 4.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

A cross-site scripting vulnerability in queryparser/termgenerator_internal.cc in Xapian xapian-core before 2.1.0 and before 1.4.32 exists due to incomplete HTML escaping by Xapian::MSet::snippet(). NOTE: this issue exists because of a missed corner case of CVE-2018-0499.

CVSS v3
4.4
EG Score
4.4MEDIUMmedium confidence
EG Risk
20
EG Risk 20/100CISA SSVC

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
Severity44% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
15th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

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

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 20, 2026

Last Modified

September 9, 2026

Advisory Details (3)

Auto-updated Aug 20, 2026
🔬 Proof of concept available. Patch available.
generic

SecurityFixes/2018-07-02 – Xapian

https://trac.xapian.org/wiki/SecurityFixes/2018-07-02#a2026-08-13update
generic🟡 PoC Available

MSet::snippet() returns unescaped text when hi_start and hi_end are both empty

https://lists.xapian.org/pipermail/xapian-devel/2026-August/003429.html
generic Patch Available

#1144490 - libxapian30: previously missed corner case of CVE-2018-0499 - Debian Bug report logs

https://bugs.debian.org/1144490

Vendor Advisories for CVE-2026-77643(1)

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

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
xapian-core1.4.22-1 ... 2.1.0-1 (19 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
xapian-core1.4.29-3
  • every version up to 1.4.29-3+deb13u1: fixed in 1.4.29-3+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
xapian-core1.4.29-3, 1.4.31-1, 1.4.31-2, 1.4.31-2~bpo13+1, 1.4.32-1~bpo13+1
  • every version up to 1.4.32-1: fixed in 1.4.32-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 16× in last 7d / 73× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 121 total refreshes for this CVE.

  1. 2026-10-05 17:43 UTCEPSS rescore
  2. 2026-10-04 23:22 UTCEPSS rescore
  3. 2026-10-04 20:51 UTCGHSA enrichment
  4. 2026-10-03 16:46 UTCEG score recompute
  5. 2026-10-03 16:46 UTCGHSA enrichment
  6. 2026-10-03 14:26 UTCEPSS rescore
  7. 2026-10-02 12:55 UTCEG score recompute
  8. 2026-10-02 12:55 UTCGHSA enrichment
  9. 2026-10-01 19:50 UTCEPSS rescore
  10. 2026-10-01 09:49 UTCEG score recompute
  11. 2026-10-01 09:49 UTCGHSA enrichment
  12. 2026-09-30 08:08 UTCEG score recompute
  13. 2026-09-30 08:08 UTCGHSA enrichment
  14. 2026-09-29 15:24 UTCEPSS rescore
  15. 2026-09-29 06:18 UTCEG score recompute
  16. 2026-09-29 06:18 UTCGHSA enrichment
  17. 2026-09-28 13:52 UTCEPSS rescore
  18. 2026-09-28 04:36 UTCEG score recompute
  19. 2026-09-28 04:36 UTCGHSA enrichment
  20. 2026-09-27 13:48 UTCEPSS rescore
  21. 2026-09-27 02:54 UTCEG score recompute
  22. 2026-09-27 02:54 UTCGHSA enrichment
  23. 2026-09-26 15:59 UTCEPSS rescore
  24. 2026-09-26 00:28 UTCEPSS rescore
  25. 2026-09-24 16:04 UTCEG score recompute
Show 75 more
  1. 2026-09-24 16:04 UTCGHSA enrichment
  2. 2026-09-24 14:04 UTCEPSS rescore
  3. 2026-09-23 17:54 UTCEPSS rescore
  4. 2026-09-23 14:22 UTCEG score recompute
  5. 2026-09-23 14:22 UTCGHSA enrichment
  6. 2026-09-22 16:01 UTCEPSS rescore
  7. 2026-09-22 12:41 UTCEG score recompute
  8. 2026-09-22 12:41 UTCGHSA enrichment
  9. 2026-09-21 21:09 UTCEPSS rescore
  10. 2026-09-21 10:58 UTCEG score recompute
  11. 2026-09-21 10:58 UTCGHSA enrichment
  12. 2026-09-20 20:16 UTCEPSS rescore
  13. 2026-09-20 09:12 UTCEG score recompute
  14. 2026-09-20 09:12 UTCGHSA enrichment
  15. 2026-09-19 07:30 UTCEG score recompute
  16. 2026-09-19 07:30 UTCGHSA enrichment
  17. 2026-09-18 19:28 UTCEPSS rescore
  18. 2026-09-18 05:49 UTCEG score recompute
  19. 2026-09-18 05:49 UTCGHSA enrichment
  20. 2026-09-17 04:07 UTCEG score recompute
  21. 2026-09-17 04:07 UTCGHSA enrichment
  22. 2026-09-16 14:08 UTCEPSS rescore
  23. 2026-09-16 05:15 UTCEPSS rescore
  24. 2026-09-16 02:23 UTCEG score recompute
  25. 2026-09-16 02:22 UTCGHSA enrichment
  26. 2026-09-15 03:12 UTCEPSS rescore
  27. 2026-09-15 03:12 UTCEPSS rescore
  28. 2026-09-15 00:40 UTCGHSA enrichment
  29. 2026-09-13 22:58 UTCEG score recompute
  30. 2026-09-13 22:58 UTCGHSA enrichment
  31. 2026-09-12 21:17 UTCEG score recompute
  32. 2026-09-12 21:17 UTCGHSA enrichment
  33. 2026-09-12 15:02 UTCEPSS rescore
  34. 2026-09-11 19:35 UTCEG score recompute
  35. 2026-09-11 19:35 UTCGHSA enrichment
  36. 2026-09-11 14:53 UTCEPSS rescore
  37. 2026-09-10 17:53 UTCEG score recompute
  38. 2026-09-10 17:53 UTCGHSA enrichment
  39. 2026-09-10 09:35 UTCEPSS rescore
  40. 2026-09-09 16:11 UTCGHSA enrichment
  41. 2026-09-09 01:53 UTCEG score recompute
  42. 2026-09-09 01:53 UTCGHSA enrichment
  43. 2026-09-08 22:01 UTCEPSS rescore
  44. 2026-09-07 15:32 UTCEG score recompute
  45. 2026-09-07 15:32 UTCGHSA enrichment
  46. 2026-09-06 13:48 UTCEPSS rescore
  47. 2026-09-06 10:55 UTCEG score recompute
  48. 2026-09-06 10:55 UTCGHSA enrichment
  49. 2026-09-05 09:14 UTCEG score recompute
  50. 2026-09-05 09:14 UTCGHSA enrichment
  51. 2026-09-04 07:32 UTCEG score recompute
  52. 2026-09-04 07:32 UTCGHSA enrichment
  53. 2026-09-04 05:07 UTCEPSS rescore
  54. 2026-09-03 05:40 UTCEG score recompute
  55. 2026-09-03 05:40 UTCGHSA enrichment
  56. 2026-09-02 14:12 UTCEPSS rescore
  57. 2026-09-02 03:36 UTCEG score recompute
  58. 2026-09-02 03:35 UTCGHSA enrichment
  59. 2026-09-01 13:54 UTCEPSS rescore
  60. 2026-09-01 04:40 UTCEPSS rescore
  61. 2026-09-01 04:40 UTCEPSS rescore
  62. 2026-09-01 01:50 UTCGHSA enrichment
  63. 2026-08-31 00:09 UTCEG score recompute
  64. 2026-08-31 00:09 UTCGHSA enrichment
  65. 2026-08-30 19:18 UTCEPSS rescore
  66. 2026-08-30 19:17 UTCEPSS rescore
  67. 2026-08-30 01:22 UTCEPSS rescore
  68. 2026-08-29 22:27 UTCEG score recompute
  69. 2026-08-29 22:27 UTCGHSA enrichment
  70. 2026-08-28 21:42 UTCEPSS rescore
  71. 2026-08-28 20:45 UTCEG score recompute
  72. 2026-08-28 20:45 UTCGHSA enrichment
  73. 2026-08-28 19:51 UTCEG score recompute
  74. 2026-08-28 19:51 UTCGHSA enrichment
  75. 2026-08-28 10:18 UTCEG score recompute

Related CVEs(same product + same CWE)

Same product

1 shown

Debian:12:xapian-core

Frequently asked(5)

What is CVE-2026-77643?
CVE-2026-77643 is a medium vulnerability published on August 20, 2026. A cross-site scripting vulnerability in queryparser/termgenerator_internal.cc in Xapian xapian-core before 2.1.0 and before 1.4.32 exists due to incomplete HTML escaping by Xapian::MSet::snippet(). NOTE: this issue exists because of a missed corner case of CVE-2018-0499.
When was CVE-2026-77643 disclosed?
CVE-2026-77643 was first published on August 20, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77643 actively exploited?
CVE-2026-77643 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (15th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77643?
CVE-2026-77643 has a CVSS base score of 4.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-77643?
A fix for CVE-2026-77643 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-77643 are linked in the Vendor Advisories panel on this page.

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