CVE-2026-54387

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-06-17. a secondary CVSS source baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
9.1EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 9.1Exploit: None knownExposed services: Not assessed

An upstream fix is merged but not yet released — mitigate (WAF / firewall / segmentation) until the release ships, then apply it.

Tinyproxy through 1.11.3, fixed in commit ff45d3b, fails to reconcile conflicting Content-Length and Transfer-Encoding: chunked headers, forwarding both verbatim to the backend while using Content-Length to determine how many request body bytes to consume. Remote attackers can desynchronize the proxy and backend parser state, allowing injection of arbitrary HTTP requests to the backend to enable cache poisoning, access control bypass, and request hijacking.

CVSS v3
9.1
EG Score
9.1CRITICALmedium confidence
EG Risk
56
EG Risk 56/100

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
Severity91% × 45%
Exploitation0% × 40%
Automatability100% × 15%
EPSS PROB
0.7%
EPSS %ILE
50th
KEV
Not listed

Published

June 17, 2026

Last Modified

July 14, 2026

Advisory Details (4)

Auto-updated Sep 16, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit, github_pr.
generic

Tinyproxy - HTTP Request Smuggling via CL/TE Desynchronization | Advisories | VulnCheck

https://www.vulncheck.com/advisories/tinyproxy-http-request-smuggling-via-cl-te-desynchronization
github_pr

Prevent request smuggling

Fix merged in tinyproxy/tinyproxy PR #610 on 2026-05-07 — awaiting tagged release

https://github.com/tinyproxy/tinyproxy/pull/610
generic

HTTP Request Smuggling: CL/TE desync + duplicate Content-Length forwarding · Issue #609 · tinyproxy/tinyproxy · GitHub

https://github.com/tinyproxy/tinyproxy/issues/609
github_commit

commit ff45d3bf0e61 (tinyproxy/tinyproxy)

Fix landed in tinyproxy/tinyproxy commit ff45d3bf0e61 — awaiting tagged release

https://github.com/tinyproxy/tinyproxy/commit/ff45d3bf0e61d0f8ed97ab379d3047f04eb67521

Vendor Advisories for CVE-2026-54387(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
tinyproxy1.10.0-5 ... 1.11.3-1~bpo13+1 (15 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
tinyproxy1.11.1-2.1 ... 1.11.3-1~bpo13+1 (8 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
tinyproxy1.11.2-1, 1.11.3-1, 1.11.3-1~bpo13+1
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
tinyproxy1.11.2-1, 1.11.3-1, 1.11.3-1~bpo13+1
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 30× 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 482 total refreshes for this CVE.

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

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-54387?
CVE-2026-54387 is a critical vulnerability published on June 17, 2026. Tinyproxy through 1.11.3, fixed in commit ff45d3b, fails to reconcile conflicting Content-Length and Transfer-Encoding: chunked headers, forwarding both verbatim to the backend while using Content-Length to determine how many request body bytes to consume. Remote attackers can desynchronize the…
When was CVE-2026-54387 disclosed?
CVE-2026-54387 was first published on June 17, 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-2026-54387 actively exploited?
CVE-2026-54387 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-2026-54387?
CVE-2026-54387 has a CVSS base score of 9.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-54387?
An upstream fix for CVE-2026-54387 has been merged but is not yet in a tagged release. Until it ships, restrict network exposure of the affected system or apply the vendor's mitigation, then update to the release that contains the fix. The vendor advisories EchelonGraph has for CVE-2026-54387 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-54387

Explore →

Is Your Infrastructure Affected by CVE-2026-54387?

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

Book a Demo →Browse All CVEs