CVE-2026-77775

HIGHPre-NVD 8.68.6—
EchelonGraph scoreMEDIUM confidence

Score 8.6 from GitHub Security Advisory (severity: HIGH) published 2026-08-21. A secondary CVSS source baseline 8.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
8.6EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 8.6Exploit: None knownExposed services: Not assessed

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

Headroom's LLM proxy lets a client choose the upstream destination with the x-headroom-base-url request header. _resolve_openai_upstream_base in headroom/proxy/handlers/openai.py accepts the header value, requires only that it parse with an http or https scheme and a hostname, and returns it for use as the upstream base; _select_passthrough_base_url in headroom/providers/proxy_routes.py reads the same header for the passthrough routes. No check rejects loopback, link-local, or RFC 1918 destinations, and because the component is a proxy the upstream response is returned to the caller, so the request reaches internal services and cloud metadata addresses and their responses are disclosed. The Authorization header accompanying the request is forwarded unchanged to the caller-designated host. The pip console script binds 127.0.0.1 by default, but the reference docker-compose.yml ships --host 0.0.0.0 with published ports and no required HEADROOM_PROXY_TOKEN, which the server itself warns about at startup, so a deployment following the shipped compose exposes the affected data-plane routes to the network without authentication.

CVSS v3
8.6
EG Score
8.6HIGHmedium confidence
EG Risk
54
EG Risk 54/100CISA 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
Severity86% × 45%
Exploitation1% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.6%
EPSS %ILE
46th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable yes (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 21, 2026

Last Modified

September 9, 2026

Advisory Details (5)

Auto-updated Aug 21, 2026
No fix on record yet. Sources: github_pr.
generic

Headroom Proxy Sends Upstream Requests to a Client-Supplied Base URL Without Address Validation | Advisories | VulnCheck

https://www.vulncheck.com/advisories/headroom-proxy-sends-upstream-requests-to-a-client-supplied-base-url-without-address-validation
genericMentions a patch (unverified)

GitHub - headroomlabs-ai/headroom: Compress tool outputs, logs, files, and RAG chunks before they reach the LLM. 20% fewer tokens for coding agents, 60-95% fewer tokens for JSON, same answers. Library, proxy, MCP server. · GitHub

https://github.com/headroomlabs-ai/headroom
generic

headroom/headroom/proxy/upstream_guard.py at v0.36.1 · headroomlabs-ai/headroom · GitHub

https://github.com/headroomlabs-ai/headroom/blob/v0.36.1/headroom/proxy/upstream_guard.py
generic

headroom/headroom/proxy/handlers/openai.py at v0.29.0 · headroomlabs-ai/headroom · GitHub

https://github.com/headroomlabs-ai/headroom/blob/v0.29.0/headroom/proxy/handlers/openai.py
github_pr

security: address u9up assessment findings (WEB-01–07)

Fix merged in headroomlabs-ai/headroom PR #2207 on 2026-08-20 — awaiting tagged release

https://github.com/headroomlabs-ai/headroom/pull/2207

Vendor Advisories for CVE-2026-77775(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 20× in last 7d / 103× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 99 of 186 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 100 is merged into the row it repeats. The 87 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  2. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  3. 2026-10-09 06:00 UTCEG score recompute
  4. 2026-10-09 06:00 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  5. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  6. 2026-10-08 04:58 UTCEG score recompute
  7. 2026-10-08 04:57 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  8. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  9. 2026-10-07 06:39 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  10. 2026-10-06 19:21 UTCEG score recompute
  11. 2026-10-06 19:21 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  12. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  13. 2026-10-06 07:49 UTCEG score recompute
  14. 2026-10-06 07:49 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  15. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  16. 2026-10-05 17:07 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  17. 2026-10-05 04:55 UTCEG score recompute
  18. 2026-10-05 04:55 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  19. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  20. 2026-10-04 15:39 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  21. 2026-10-04 04:02 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  22. 2026-10-03 16:43 UTCEG score recompute
  23. 2026-10-03 16:43 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  24. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  25. 2026-10-02 20:59 UTCEG score recompute
Show 74 more
  1. 2026-10-02 20:59 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  2. 2026-10-02 08:43 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  3. 2026-10-01 21:25 UTCEG score recompute
  4. 2026-10-01 21:25 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  5. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  6. 2026-10-01 07:46 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  7. 2026-09-30 20:29 UTCEG score recompute
  8. 2026-09-30 20:29 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  9. 2026-09-30 07:57 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  10. 2026-09-29 16:15 UTCEG score recompute
  11. 2026-09-29 16:15 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  12. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  13. 2026-09-29 00:37 UTCEG score recompute
  14. 2026-09-29 00:37 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  15. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  16. 2026-09-28 13:19 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  17. 2026-09-28 02:02 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  18. 2026-09-27 14:44 UTCEG score recompute
  19. 2026-09-27 14:44 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  20. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  21. 2026-09-27 02:31 UTCEG score recompute
  22. 2026-09-27 02:31 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  23. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  24. 2026-09-26 00:28 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  25. 2026-09-25 06:20 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  26. 2026-09-24 19:02 UTCEG score recompute
  27. 2026-09-24 19:02 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  28. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  29. 2026-09-24 07:20 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  30. 2026-09-23 20:02 UTCEG score recompute
  31. 2026-09-23 20:02 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  32. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  33. 2026-09-23 07:01 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  34. 2026-09-22 19:43 UTCEG score recompute
  35. 2026-09-22 19:43 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  36. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  37. 2026-09-22 05:08 UTCEG score recompute
  38. 2026-09-22 05:08 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  39. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  40. 2026-09-21 17:50 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  41. 2026-09-21 05:45 UTCEG score recompute
  42. 2026-09-21 05:45 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  43. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  44. 2026-09-20 17:07 UTCEG score recompute
  45. 2026-09-20 17:07 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  46. 2026-09-20 05:49 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  47. 2026-09-19 18:31 UTCEG score recompute
  48. 2026-09-19 18:31 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  49. 2026-09-19 07:14 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  50. 2026-09-18 19:56 UTCEG score recompute
  51. 2026-09-18 19:56 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  52. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  53. 2026-09-18 08:36 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  54. 2026-09-17 21:17 UTCEG score recompute
  55. 2026-09-17 21:17 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  56. 2026-09-17 09:59 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  57. 2026-09-16 22:41 UTCEG score recompute
  58. 2026-09-16 22:41 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  59. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  60. 2026-09-16 11:08 UTCEG score recompute
  61. 2026-09-16 11:08 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  62. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  63. 2026-09-15 23:50 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  64. 2026-09-15 12:28 UTCEG score recompute
  65. 2026-09-15 12:28 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  66. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  67. 2026-09-15 01:10 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  68. 2026-09-14 13:52 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  69. 2026-09-14 02:34 UTCEG score recompute
  70. 2026-09-14 02:34 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  71. 2026-09-13 15:16 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  72. 2026-09-13 03:57 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  73. 2026-09-12 16:39 UTCEG score recompute
  74. 2026-09-12 16:39 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-77775?
CVE-2026-77775 is a high vulnerability published on August 21, 2026. Headroom's LLM proxy lets a client choose the upstream destination with the x-headroom-base-url request header. resolveopenaiupstreambase in headroom/proxy/handlers/openai.py accepts the header value, requires only that it parse with an http or https scheme and a hostname, and returns it for use as…
When was the CVE record for CVE-2026-77775 published?
The CVE record for CVE-2026-77775 was published on August 21, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 9, 2026; the record at its source may have been updated since.
Is CVE-2026-77775 actively exploited?
CVE-2026-77775 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (46th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77775?
CVE-2026-77775 has a CVSS base score of 8.6 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-77775?
No fix for CVE-2026-77775 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-77775 are linked in the Vendor Advisories panel on this page.

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