CVE-2026-56858

MEDIUMPre-NVD 6.16.1—
EchelonGraph scoreMEDIUM confidence

Score 6.1 from GitHub Security Advisory published 2026-08-14. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 6.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — Patch released this week
6.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 6.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Previously, pathological inputs could close an unescaped '/' early, allowing for attack-controlled data to inject arbitrary content, potentially leading to XSS.

CVSS v3
6.1
EG Score
6.1MEDIUMmedium confidence
EG Risk
28
EG Risk 28/100CISA 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
Severity61% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
21st
KEV
Not listed

CISA SSVCTrack 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). 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 13, 2026

Last Modified

September 3, 2026

Advisory Details (4)

Auto-updated Aug 14, 2026
Patch available.
generic

GO-2026-6091 - Go Packages

https://pkg.go.dev/vuln/GO-2026-6091
generic
https://groups.google.com/g/golang-announce/c/94pEornpRlI
generic
https://go.dev/cl/807100
generic

html/template: potential XSS caused by wrong JavaScript regexp context tracking after top-level `{` · Issue #80435 · golang/go · GitHub

https://go.dev/issue/80435

Vendor Advisories for CVE-2026-56858(20)

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

Patch Availability(27)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatyggdrasil-worker-forwarder-0:0.1.0-2.1.el9sat2026-10-01redhat
redhatopenshift4/ose-vsphere-problem-detector-rhel9:17899376292026-10-01redhat
redhatose-azure-acr-image-credential-provider-0:4.18.0-202609081426.p2.g9795abd.assembly.stream.el82026-10-01redhat
redhatopenshift4/ose-vsphere-problem-detector-rhel9:17899037652026-10-01redhat
redhatsatellite/iop-vmaas-rhel9:17908181572026-10-01redhat
redhatquay/quay-rhel9:17906902982026-10-01redhat
redhatose-azure-acr-image-credential-provider-0:4.17.0-202609081428.p2.g5bcfbfd.assembly.stream.el82026-10-01redhat
redhatcompliance/openshift-file-integrity-rhel8-operator:17902892632026-09-30redhat
redhatrhoai/odh-workbench-jupyter-trustyai-cpu-py312-rhel9:17902609542026-09-30redhat
redhatrh-lightspeed-runtimes/runtimes-inventory-rhel9-operator:17901941222026-09-29redhat
redhatcontainer-native-virtualization/kubemacpool-rhel9:17902517712026-09-29redhat
redhatmulticluster-globalhub/multicluster-globalhub-agent-rhel9:17906386122026-09-29redhat
redhatose-azure-acr-image-credential-provider-0:4.21.0-202609221600.p2.g53d73b1.assembly.stream.el102026-09-29redhat
redhatmicroshift-0:4.22.16-202609250657.p0.g3898bb2.assembly.4.22.16.el92026-09-29redhat
redhatcontainer-native-virtualization/kubemacpool-rhel9:17900603162026-09-29redhat
redhatopenshift-clients-0:4.22.0-202609170632.p2.gd0f23b1.assembly.stream.el82026-09-29redhat
redhatmulticluster-globalhub/multicluster-globalhub-agent-rhel9:17900854942026-09-29redhat
redhatrhacm2/thanos-rhel9:17901781062026-09-28redhat
redhatmulticluster-engine/discovery-rhel9:17901309732026-09-28redhat
redhatmulticluster-engine/discovery-rhel9:17901345102026-09-28redhat
redhatmulticluster-engine/discovery-rhel9:17901176532026-09-28redhat
redhatrhacm2/thanos-rhel9:17901984082026-09-28redhat
redhatmulticluster-engine/discovery-rhel9:17901212872026-09-28redhat
redhatmulticluster-engine/discovery-rhel9:17901262442026-09-28redhat
redhatbuildah-2:1.43.3-2.el9_82026-09-24redhat
redhatopenshift4/ose-vsphere-problem-detector-rhel9:17893620322026-09-24redhat
redhatmulticluster-globalhub/multicluster-globalhub-agent-rhel9:17895154082026-09-24redhat

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

(6 across 4 ecosystems)
Debian:14(3)
PackageVulnerable rangeFix by version rangeDependents
golang-1.251.25.0-1 ... 1.25.9-1 (20 versions)
  • every version on: no fix on record
—
golang-1.261.26.0-1 ... 1.26~rc3-2 (16 versions)
  • every version up to 1.26.6-1: fixed in 1.26.6-1
—
golang-1.271.27~rc1-1, 1.27~rc2-1
  • every version up to 1.27~rc3-1: fixed in 1.27~rc3-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
golang-1.191.19.10-1 ... 1.19.9-1 (12 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
golang-1.241.24.12-1 ... 1.24.9-1 (10 versions)
  • every version on: no fix on record
—
Go(1)
PackageVulnerable rangeFix by version rangeDependents
stdlib—
  • every version up to 1.25.13: fixed in 1.25.13
  • 1.26.0-0 up to 1.26.6: fixed in 1.26.6
  • 1.27.0-0 up to 1.27.0-rc.3: fixed in 1.27.0-rc.3
—

Weakness Classification(1)

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

All Vendor Advisories

(25)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 18× in last 7d / 96× 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 180 total refreshes for this CVE.

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

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-56858?
CVE-2026-56858 is a medium vulnerability published on August 13, 2026. Previously, pathological inputs could close an unescaped '/' early, allowing for attack-controlled data to inject arbitrary content, potentially leading to XSS.
When was CVE-2026-56858 disclosed?
CVE-2026-56858 was first published on August 13, 2026, with the most recent update on September 3, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-56858 actively exploited?
CVE-2026-56858 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (21st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-56858?
CVE-2026-56858 has a CVSS v3.1 base score of 6.1 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-56858?
A fix for CVE-2026-56858 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-56858 are linked in the Vendor Advisories panel on this page.

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