CVE-2026-55204

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-06-18. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

A fix is available — apply it.

HAProxy through 3.4.0, fixed in commit 9a6d1fe, contains a null pointer dereference vulnerability in hpack_dht_insert() within src/hpack-tbl.c that fails to validate the return value of hpack_dht_defrag() when the memory pool is exhausted. An attacker can trigger HPACK dynamic table insertions under memory pressure to dereference a NULL pointer and crash HAProxy worker processes, causing denial of service.

CVSS v3
7.5
EG Score
7.5(high)
EPSS
34.7%
KEV
Not listed

Published

June 18, 2026

Last Modified

June 26, 2026

Advisory Details (2)

Auto-updated Jun 18, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
generic

HAProxy - NULL Pointer Dereference in hpack_dht_insert Function | Advisories | VulnCheck

https://www.vulncheck.com/advisories/haproxy-null-pointer-dereference-in-hpack-dht-insert-function
github_commit

commit 9a6d1fe3f00d (haproxy/haproxy)

Fix landed in haproxy/haproxy commit 9a6d1fe3f00d — awaiting tagged release

https://github.com/haproxy/haproxy/commit/9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513

Vendor Advisories for CVE-2026-55204(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 / EcosystemFixed in / PatchReleasedSource
ubuntuvim-haproxy (3.2.9-1ubuntu2.2) @ resolute2026-07-07ubuntu

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.

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 54× in last 7d / 120× 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 120 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-55204?
CVE-2026-55204 is a high vulnerability published on June 18, 2026. HAProxy through 3.4.0, fixed in commit 9a6d1fe, contains a null pointer dereference vulnerability in hpackdhtinsert() within src/hpack-tbl.c that fails to validate the return value of hpackdhtdefrag() when the memory pool is exhausted. An attacker can trigger HPACK dynamic table insertions under…
When was CVE-2026-55204 disclosed?
CVE-2026-55204 was first published in the National Vulnerability Database on June 18, 2026, with the most recent update on June 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55204 actively exploited?
CVE-2026-55204 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 34.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-55204?
CVE-2026-55204 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-55204?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55204, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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