CVE-2026-55204

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM 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
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 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(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

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
Severity75% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
40%
KEV
Not listed

Published

June 18, 2026

Last Modified

July 14, 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(12)

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

Patch Availability(12)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuvim-haproxy (3.0.12-0ubuntu0.25.10.5) @ questing2026-08-30ubuntu
redhathaproxy-0:3.0.5-4.el10_0.32026-08-17redhat
redhathaproxy-0:1.8.27-4.el8_6.22026-08-17redhat
redhathaproxy-0:1.8.27-5.el8_8.22026-08-17redhat
redhathaproxy-0:2.8.14-3.el9_8.22026-08-17redhat
redhathaproxy-0:2.4.17-6.el9_2.52026-08-17redhat
redhathaproxy-0:3.0.5-6.el10_2.22026-08-17redhat
redhathaproxy-0:1.8.27-5.el8_10.22026-08-17redhat
redhathaproxy-0:1.8.27-2.el8_4.22026-08-17redhat
redhathaproxy-0:2.4.22-3.el9_4.32026-08-17redhat
redhathaproxy-0:2.4.22-4.el9_6.32026-08-17redhat
redhathaproxy-main-3.0.25-0.1.hum12026-07-03redhat

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 rangeFixed inDependents
haproxy2.2.16-1 ... 3.4.3-1 (180 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
haproxy2.6.12-1 ... 3.4.4-1 (102 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
haproxy3.0.11-1 ... 3.4.4-1 (55 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
haproxy3.0.11-1 ... 3.2.9-1 (31 versions)3.2.20-1—

Weakness Classification(1)

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

Additional Vendor Advisories

(3)

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 5× in last 7d / 78× 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 325 total refreshes for this CVE.

  1. 2026-09-11 14:53 UTCEPSS rescore
  2. 2026-09-10 09:35 UTCEPSS rescore
  3. 2026-09-08 22:01 UTCEPSS rescore
  4. 2026-09-07 16:01 UTCEPSS rescore
  5. 2026-09-06 13:47 UTCEPSS rescore
  6. 2026-09-04 05:06 UTCEPSS rescore
  7. 2026-09-02 14:12 UTCEPSS rescore
  8. 2026-09-01 13:54 UTCEPSS rescore
  9. 2026-09-01 04:40 UTCEPSS rescore
  10. 2026-08-30 20:55 UTCEG score recompute
  11. 2026-08-30 20:55 UTCVendor advisory
  12. 2026-08-30 20:55 UTCGHSA enrichment
  13. 2026-08-30 19:17 UTCEPSS rescore
  14. 2026-08-30 01:22 UTCEPSS rescore
  15. 2026-08-28 21:41 UTCEPSS rescore
  16. 2026-08-27 14:25 UTCEPSS rescore
  17. 2026-08-26 14:46 UTCEPSS rescore
  18. 2026-08-25 13:49 UTCEPSS rescore
  19. 2026-08-25 02:29 UTCVendor advisory
  20. 2026-08-25 02:29 UTCGHSA enrichment
  21. 2026-08-24 15:02 UTCEG score recompute
  22. 2026-08-24 15:02 UTCVendor advisory
  23. 2026-08-24 15:02 UTCGHSA enrichment
  24. 2026-08-24 00:04 UTCVendor advisory
  25. 2026-08-24 00:03 UTCGHSA enrichment
Show 75 more
  1. 2026-08-23 12:34 UTCVendor advisory
  2. 2026-08-23 12:34 UTCGHSA enrichment
  3. 2026-08-23 01:07 UTCEG score recompute
  4. 2026-08-23 01:07 UTCVendor advisory
  5. 2026-08-23 01:07 UTCGHSA enrichment
  6. 2026-08-23 00:19 UTCEPSS rescore
  7. 2026-08-21 23:49 UTCEPSS rescore
  8. 2026-08-21 18:49 UTCVendor advisory
  9. 2026-08-21 18:49 UTCGHSA enrichment
  10. 2026-08-21 07:22 UTCEG score recompute
  11. 2026-08-21 07:22 UTCVendor advisory
  12. 2026-08-21 07:22 UTCGHSA enrichment
  13. 2026-08-20 22:55 UTCEPSS rescore
  14. 2026-08-20 19:35 UTCVendor advisory
  15. 2026-08-20 19:35 UTCGHSA enrichment
  16. 2026-08-20 08:08 UTCEG score recompute
  17. 2026-08-20 08:08 UTCVendor advisory
  18. 2026-08-20 08:08 UTCGHSA enrichment
  19. 2026-08-19 17:04 UTCEPSS rescore
  20. 2026-08-19 07:43 UTCEG score recompute
  21. 2026-08-19 07:43 UTCVendor advisory
  22. 2026-08-19 07:43 UTCGHSA enrichment
  23. 2026-08-18 13:48 UTCEPSS rescore
  24. 2026-08-17 13:47 UTCEPSS rescore
  25. 2026-08-17 08:08 UTCVendor advisory
  26. 2026-08-17 08:08 UTCGHSA enrichment
  27. 2026-08-16 20:41 UTCEG score recompute
  28. 2026-08-16 20:41 UTCVendor advisory
  29. 2026-08-16 20:41 UTCGHSA enrichment
  30. 2026-08-16 14:56 UTCEPSS rescore
  31. 2026-08-16 08:35 UTCEG score recompute
  32. 2026-08-16 08:35 UTCVendor advisory
  33. 2026-08-16 08:35 UTCGHSA enrichment
  34. 2026-08-16 02:14 UTCEPSS rescore
  35. 2026-08-15 21:08 UTCVendor advisory
  36. 2026-08-15 21:08 UTCGHSA enrichment
  37. 2026-08-15 09:04 UTCEG score recompute
  38. 2026-08-15 09:04 UTCVendor advisory
  39. 2026-08-15 09:04 UTCGHSA enrichment
  40. 2026-08-15 01:30 UTCEPSS rescore
  41. 2026-08-14 19:41 UTCVendor advisory
  42. 2026-08-14 19:41 UTCGHSA enrichment
  43. 2026-08-14 08:14 UTCEG score recompute
  44. 2026-08-14 08:14 UTCVendor advisory
  45. 2026-08-14 08:14 UTCGHSA enrichment
  46. 2026-08-13 22:00 UTCEPSS rescore
  47. 2026-08-13 20:47 UTCVendor advisory
  48. 2026-08-13 20:47 UTCGHSA enrichment
  49. 2026-08-13 09:20 UTCVendor advisory
  50. 2026-08-13 09:20 UTCGHSA enrichment
  51. 2026-08-12 21:53 UTCEG score recompute
  52. 2026-08-12 21:53 UTCVendor advisory
  53. 2026-08-12 21:53 UTCGHSA enrichment
  54. 2026-08-12 13:51 UTCEPSS rescore
  55. 2026-08-12 10:26 UTCVendor advisory
  56. 2026-08-12 10:26 UTCGHSA enrichment
  57. 2026-08-11 22:58 UTCEG score recompute
  58. 2026-08-11 22:58 UTCVendor advisory
  59. 2026-08-11 22:58 UTCGHSA enrichment
  60. 2026-08-11 11:31 UTCVendor advisory
  61. 2026-08-11 11:31 UTCGHSA enrichment
  62. 2026-08-11 00:04 UTCEG score recompute
  63. 2026-08-11 00:04 UTCVendor advisory
  64. 2026-08-11 00:04 UTCGHSA enrichment
  65. 2026-08-11 00:00 UTCEPSS rescore
  66. 2026-08-10 12:36 UTCVendor advisory
  67. 2026-08-10 12:36 UTCGHSA enrichment
  68. 2026-08-10 01:09 UTCEG score recompute
  69. 2026-08-10 01:09 UTCVendor advisory
  70. 2026-08-10 01:09 UTCGHSA enrichment
  71. 2026-08-09 13:46 UTCEPSS rescore
  72. 2026-08-09 13:42 UTCVendor advisory
  73. 2026-08-09 13:42 UTCGHSA enrichment
  74. 2026-08-09 02:15 UTCVendor advisory
  75. 2026-08-09 02:15 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 July 14, 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 0% probability of exploitation in the next 30 days, which ranks it in the top 59.8% of all scored CVEs.
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.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-55204

Explore →

Is Your Infrastructure Affected by CVE-2026-55204?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs