CVE-2026-58055

MEDIUMPre-NVD 5.45.4
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 5.4 from GitHub Security Advisory published 2026-06-28. A secondary CVSS source baseline 5.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 4 sources updated this week

Also known asEUVD-2026-39975 (ENISA EUVD) · GHSA-xrr7-82jr-v58x (GitHub Security Advisories)Source: ENISA EUVD

5.4EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 5.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting ambiguous message in the attacker's favor enables HTTP request/response smuggling and cross-client response-queue poisoning.

CVSS v3
5.4
EG Score
5.4MEDIUMmedium confidence
EG Risk
24
EG Risk 24/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity54% × 45%
Impact severity (EG Severity): CVSS 5.4 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
16th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.4): severity, escalated by confirmed exploitation. This CVE's 5.4 is its impact severity (EG Severity), not escalated.

EG Severity
5.4 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-29). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

June 28, 2026

Last Modified

October 25, 2026

Advisory Details (3)

Auto-updated Jun 28, 2026
Patch available. Sources: github_commit.
Web page

nghttp2 nghttpx - HTTP Request/Response Smuggling via Upgrade Request with Content-Length | Advisories | VulnCheck

https://www.vulncheck.com/advisories/nghttp2-nghttpx-http-request-response-smuggling-via-upgrade-request-with-content-length
GitHub commit

commit ab28105c4a01 (nghttp2/nghttp2)

Fix landed in nghttp2/nghttp2 commit ab28105c4a01 — awaiting tagged release

https://github.com/nghttp2/nghttp2/commit/ab28105c4a0197da24f8bfc414bc116055249e1e
Web page

exploitarium/nghttp2-nghttpx-upgrade-queue-poison-poc at main · bikini/exploitarium · GitHub

https://github.com/bikini/exploitarium/tree/main/nghttp2-nghttpx-upgrade-queue-poison-poc

Patch Availability(29)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntunghttp2-server (1.59.0-1ubuntu0.4) @ noble2026-10-29ubuntu
redhatnghttp2-main-1.70.0-0.1.hum12026-10-21redhat
redhatcert-manager/cert-manager-operator-bundle:17919662592026-10-14redhat
redhatcert-manager/cert-manager-operator-bundle:17919704842026-10-14redhat
redhatcert-manager/cert-manager-istio-csr-rhel9:17914597592026-10-13redhat
redhatcert-manager/cert-manager-istio-csr-rhel9:17913783952026-10-13redhat
redhatcert-manager/cert-manager-operator-rhel9:17917882872026-10-13redhat
redhatcert-manager/cert-manager-operator-rhel9:17890290762026-10-13redhat
redhatcert-manager/jetstack-cert-manager-rhel9:17914597112026-10-13redhat
redhatcert-manager/jetstack-cert-manager-rhel9:17913710692026-10-13redhat
redhatcert-manager/jetstack-cert-manager-rhel9:17902232792026-09-28redhat
redhatcert-manager/cert-manager-operator-rhel9:17905898552026-09-28redhat
redhatcert-manager/cert-manager-operator-rhel9:17902724262026-09-28redhat
redhatcert-manager/cert-manager-istio-csr-rhel9:17905899142026-09-28redhat
redhatcert-manager/cert-manager-trust-manager-rhel9:17905985932026-09-28redhat
redhatcert-manager/cert-manager-istio-csr-rhel9:17902237192026-09-28redhat
redhatcert-manager/jetstack-cert-manager-rhel9:17905899122026-09-28redhat
redhatrhui5/rhua-rhel9:17888805812026-09-09redhat
redhatcert-manager/cert-manager-operator-rhel9:17883485222026-09-03redhat
redhatcert-manager/cert-manager-istio-csr-rhel9:17883485942026-09-03redhat
redhatcert-manager/jetstack-cert-manager-rhel9:17883485712026-09-03redhat
redhatdiscovery/discovery-ui-rhel9:17882061962026-08-31redhat
redhatrhui5/rhua-tp-rhel9:17872412602026-08-24redhat
redhatnghttp2-0:1.33.0-6.el8_10.32026-08-17redhat
redhatnghttp2-0:1.68.0-3.el10_2.22026-08-13redhat
redhatnghttp2-0:1.43.0-6.el9_8.22026-08-13redhat
redhatnghttp2-main-1.69.0-5.hum12026-08-10redhat
redhatcurl-main-8.21.0-0.1.1.hum12026-07-17redhat
redhatnghttp2-main-1.69.0-3.1.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

(5 across 5 ecosystems)
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
nghttp2—
  • every version up to 1.70.0-r0: fixed in 1.70.0-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
nghttp21.43.0-1 ... 1.70.0-1 (30 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
nghttp21.52.0-1 ... 1.70.0-1 (23 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
nghttp21.64.0-1.1 ... 1.70.0-1 (7 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
nghttp21.64.0-1.1, 1.68.0-1, 1.68.0-2, 1.68.1-1, 1.69.0-1
  • every version up to 1.70.0-1: fixed in 1.70.0-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(9)

Data Freshness Timeline

(refreshed 10× in last 7d / 46× 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 100 of 301 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. None are among the latest 100 rows. The 201 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  2. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  3. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  4. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  5. 2026-10-29 16:37 UTCEG score recompute
  6. 2026-10-29 16:37 UTCVendor advisory
  7. 2026-10-29 16:37 UTCGHSA enrichmentGHSA-xrr7-82jr-v58x · GitHub CVSS 5.4
  8. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  9. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  10. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  11. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  12. 2026-10-25 17:36 UTCEG score recompute
  13. 2026-10-25 17:36 UTCVendor advisory
  14. 2026-10-25 17:36 UTCGHSA enrichmentGHSA-xrr7-82jr-v58x · GitHub CVSS 5.4
  15. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  16. 2026-10-25 14:17 UTCEG score recompute
  17. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  18. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  19. 2026-10-22 21:03 UTCEG score recompute
  20. 2026-10-22 21:03 UTCVendor advisory
  21. 2026-10-22 21:02 UTCGHSA enrichmentGHSA-xrr7-82jr-v58x · GitHub CVSS 5.4
  22. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  23. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  24. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  25. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.3% · 15th percentile
Show 75 more
  1. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  2. 2026-10-18 03:28 UTCEG score recompute
  3. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  4. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  5. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  6. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  7. 2026-10-13 18:54 UTCOSV refresh
  8. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  9. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  10. 2026-10-12 15:53 UTCEG score recompute
  11. 2026-10-11 19:37 UTCEG score recompute
  12. 2026-10-11 16:52 UTCEG score recompute
  13. 2026-10-11 14:14 UTCEG score recompute
  14. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  15. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  16. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  17. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  18. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  19. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  20. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  21. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  22. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  23. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  24. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  25. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  26. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  27. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  28. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  29. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  30. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  31. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  32. 2026-09-23 07:39 UTCEG score recompute
  33. 2026-09-23 07:39 UTCVendor advisory
  34. 2026-09-23 07:39 UTCGHSA enrichmentGHSA-xrr7-82jr-v58x · GitHub CVSS 5.4
  35. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  36. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  37. 2026-09-18 07:06 UTCEG score recompute
  38. 2026-09-18 07:06 UTCVendor advisory
  39. 2026-09-18 07:06 UTCGHSA enrichmentGHSA-xrr7-82jr-v58x · GitHub CVSS 5.4
  40. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  41. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  42. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  43. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  44. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  45. 2026-09-13 13:07 UTCVendor advisory
  46. 2026-09-13 13:07 UTCGHSA enrichmentGHSA-xrr7-82jr-v58x · GitHub CVSS 5.4
  47. 2026-09-12 15:18 UTCEG score recompute
  48. 2026-09-12 15:18 UTCVendor advisory
  49. 2026-09-12 15:18 UTCGHSA enrichmentGHSA-xrr7-82jr-v58x · GitHub CVSS 5.4
  50. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  51. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  52. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  53. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  54. 2026-09-06 14:48 UTCEG score recompute
  55. 2026-09-06 14:48 UTCVendor advisory
  56. 2026-09-06 14:48 UTCGHSA enrichmentGHSA-xrr7-82jr-v58x · GitHub CVSS 5.4
  57. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  58. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  59. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  60. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  61. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  62. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  63. 2026-08-30 19:11 UTCEG score recompute
  64. 2026-08-30 19:11 UTCVendor advisory
  65. 2026-08-30 19:11 UTCGHSA enrichmentGHSA-xrr7-82jr-v58x · GitHub CVSS 5.4
  66. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  67. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  68. 2026-08-27 22:51 UTCEG score recompute
  69. 2026-08-27 22:51 UTCVendor advisory
  70. 2026-08-27 22:51 UTCGHSA enrichmentGHSA-xrr7-82jr-v58x · GitHub CVSS 5.4
  71. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  72. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  73. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  74. 2026-08-25 02:44 UTCEG score recompute
  75. 2026-08-25 02:44 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-58055?
CVE-2026-58055 is a medium-severity vulnerability; its CVE record was published on June 28, 2026. nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting…
When was CVE-2026-58055 made public?
CVE-2026-58055 was made public on June 26, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on June 28, 2026. EchelonGraph's copy of the record carries a last-modified date of October 25, 2026; the record at its source may have been updated since.
Is CVE-2026-58055 actively exploited?
CVE-2026-58055 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (16th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-58055?
CVE-2026-58055 has a CVSS base score of 5.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-58055?
A fix for CVE-2026-58055 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-58055 are linked in the Vendor Advisories panel on this page.

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