CVE-2026-55951

HIGHPre-NVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 68% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.2Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

The Erlang/OTP httpc HTTP client does not enforce a limit on the total size of response headers received from a server. The max_header_size option defaults to nolimit, and httpc_response:parse_headers/6 accumulates every header into a list before the length check runs (which only fires after the terminating CRLF CRLF is received).

A malicious or compromised HTTP server can send an arbitrarily large number of headers, or headers with very large values, causing the client process to allocate unbounded memory until the system runs out of memory or the BEAM VM crashes. A proof-of-concept server sending 100,000 headers of roughly 4000 bytes each caused the client VM to allocate over 13 GB of memory in under 30 seconds.

Any application using httpc:request/4,5 to connect to untrusted servers is affected. No authentication is required: any server the client connects to (including via a redirect or man-in-the-middle) can trigger the exhaustion.

This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before 9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.

CVSS v3
8.2
EG Score
8.2(medium)
EG Risk
37(Track)
EG Risk 37/100SSVC: 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
Severity82% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
32%
KEV
Not listed

Published

September 1, 2026

Last Modified

September 8, 2026

Advisory Details (6)

Auto-updated Sep 1, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit.
github_commit

commit e3be1cfe9f6c (erlang/otp)

Fix landed in erlang/otp commit e3be1cfe9f6c — awaiting tagged release

https://github.com/erlang/otp/commit/e3be1cfe9f6cedd0cd20d9905e05601dfb31c8aa
github_commit

commit aba0fe8c2d70 (erlang/otp)

Fix landed in erlang/otp commit aba0fe8c2d70 — awaiting tagged release

https://github.com/erlang/otp/commit/aba0fe8c2d700bf4ac94607cf7f00e53bbe4042d
generic

Versions — Erlang System Documentation v29.0.6

https://www.erlang.org/doc/system/versions.html#order-of-versions
generic🟡 PoC Available

OSV - Open Source Vulnerabilities

https://osv.dev/vulnerability/EEF-CVE-2026-55951
generic🟡 PoC Available

CVE-2026-55951

https://cna.erlef.org/cves/CVE-2026-55951.html
github Patch Available

httpc Memory Exhaustion via Unbounded Header Accumulation · Advisory · erlang/otp · GitHub

https://github.com/erlang/otp/security/advisories/GHSA-f9fw-mg7q-4g3x

Vendor Advisories for CVE-2026-55951(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 rangeFixed inDependents
erlang1:25.2.3+dfsg-1 ... 1:29.0~rc3+dfsg-4 (79 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
erlang1:27.3.4.1+dfsg-1 ... 1:29.0~rc3+dfsg-4 (40 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
erlang1:27.3.4.1+dfsg-1 ... 1:29.0~rc3+dfsg-4 (37 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 30× in last 7d / 74× 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.

  1. 2026-09-21 01:42 UTCEG score recompute
  2. 2026-09-21 01:42 UTCVendor advisory
  3. 2026-09-20 20:16 UTCEPSS rescore
  4. 2026-09-20 14:42 UTCVendor advisory
  5. 2026-09-20 03:42 UTCVendor advisory
  6. 2026-09-19 16:43 UTCEG score recompute
  7. 2026-09-19 16:43 UTCVendor advisory
  8. 2026-09-19 05:44 UTCEG score recompute
  9. 2026-09-19 05:44 UTCVendor advisory
  10. 2026-09-18 19:28 UTCEPSS rescore
  11. 2026-09-18 18:44 UTCVendor advisory
  12. 2026-09-18 07:44 UTCVendor advisory
  13. 2026-09-17 20:44 UTCEG score recompute
  14. 2026-09-17 20:44 UTCVendor advisory
  15. 2026-09-17 19:31 UTCEPSS rescore
  16. 2026-09-17 08:43 UTCVendor advisory
  17. 2026-09-16 21:44 UTCEG score recompute
  18. 2026-09-16 21:44 UTCVendor advisory
  19. 2026-09-16 14:08 UTCEPSS rescore
  20. 2026-09-16 10:44 UTCEG score recompute
  21. 2026-09-16 10:44 UTCVendor advisory
  22. 2026-09-16 05:15 UTCEPSS rescore
  23. 2026-09-15 23:35 UTCVendor advisory
  24. 2026-09-15 12:35 UTCEG score recompute
  25. 2026-09-15 12:35 UTCVendor advisory
Show 49 more
  1. 2026-09-15 03:11 UTCEPSS rescore
  2. 2026-09-15 01:34 UTCVendor advisory
  3. 2026-09-14 14:34 UTCVendor advisory
  4. 2026-09-14 03:34 UTCEG score recompute
  5. 2026-09-14 03:34 UTCVendor advisory
  6. 2026-09-13 16:47 UTCEPSS rescore
  7. 2026-09-13 16:35 UTCVendor advisory
  8. 2026-09-13 05:35 UTCVendor advisory
  9. 2026-09-12 18:36 UTCEG score recompute
  10. 2026-09-12 18:36 UTCVendor advisory
  11. 2026-09-12 07:36 UTCVendor advisory
  12. 2026-09-11 20:35 UTCEG score recompute
  13. 2026-09-11 20:35 UTCVendor advisory
  14. 2026-09-11 14:53 UTCEPSS rescore
  15. 2026-09-10 11:36 UTCEG score recompute
  16. 2026-09-10 09:35 UTCEPSS rescore
  17. 2026-09-09 11:25 UTCVendor advisory
  18. 2026-09-09 00:24 UTCEG score recompute
  19. 2026-09-09 00:24 UTCVendor advisory
  20. 2026-09-08 22:01 UTCEPSS rescore
  21. 2026-09-08 12:59 UTCVendor advisory
  22. 2026-09-08 01:28 UTCEG score recompute
  23. 2026-09-08 01:28 UTCVendor advisory
  24. 2026-09-08 01:15 UTCEG score recompute
  25. 2026-09-08 01:15 UTCVendor advisory
  26. 2026-09-07 21:16 UTCEG score recompute
  27. 2026-09-07 21:16 UTCVendor advisory
  28. 2026-09-07 16:01 UTCEPSS rescore
  29. 2026-09-07 10:16 UTCVendor advisory
  30. 2026-09-06 23:15 UTCEG score recompute
  31. 2026-09-06 23:15 UTCVendor advisory
  32. 2026-09-06 13:47 UTCEPSS rescore
  33. 2026-09-06 12:15 UTCVendor advisory
  34. 2026-09-06 01:11 UTCEG score recompute
  35. 2026-09-06 01:11 UTCVendor advisory
  36. 2026-09-05 14:11 UTCVendor advisory
  37. 2026-09-05 03:11 UTCVendor advisory
  38. 2026-09-04 16:09 UTCEG score recompute
  39. 2026-09-04 16:09 UTCVendor advisory
  40. 2026-09-04 05:07 UTCEPSS rescore
  41. 2026-09-04 05:06 UTCVendor advisory
  42. 2026-09-03 18:06 UTCVendor advisory
  43. 2026-09-02 20:00 UTCEG score recompute
  44. 2026-09-02 14:12 UTCEPSS rescore
  45. 2026-09-01 16:25 UTCEG score recompute
  46. 2026-09-01 16:10 UTCEG score recompute
  47. 2026-09-01 15:40 UTCEG score recompute
  48. 2026-09-01 14:44 UTCEG score recompute
  49. 2026-09-01 14:43 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55951?
CVE-2026-55951 is a high vulnerability published on September 1, 2026. The Erlang/OTP httpc HTTP client does not enforce a limit on the total size of response headers received from a server. The maxheadersize option defaults to nolimit, and httpcresponse:parseheaders/6 accumulates every header into a list before the length check runs (which only fires after the…
When was CVE-2026-55951 disclosed?
CVE-2026-55951 was first published in the National Vulnerability Database on September 1, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55951 actively exploited?
CVE-2026-55951 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 67.9% of all scored CVEs.
What is the CVSS score of CVE-2026-55951?
CVE-2026-55951 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-55951?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55951, 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

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