CVE-2026-27135

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.9% (59th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source

Also known asEUVD-2026-12919 (ENISA EUVD)Source: ENISA EUVD

7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.9%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

nghttp2 is an implementation of the Hypertext Transfer Protocol version 2 in C. Prior to version 1.68.1, the nghttp2 library stops reading the incoming data when user facing public API nghttp2_session_terminate_session or nghttp2_session_terminate_session2 is called by the application. They might be called internally by the library when it detects the situation that is subject to connection error. Due to the missing internal state validation, the library keeps reading the rest of the data after one of those APIs is called. Then receiving a malformed frame that causes FRAME_SIZE_ERROR causes assertion failure. nghttp2 v1.68.1 adds missing state validation to avoid assertion failure. No known workarounds are available.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
49
EG Risk 49/100

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)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.8% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.9%
EPSS %ILE
59th
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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.9% within 30 daysSource: FIRST EPSS. 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 low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days 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 low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (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

March 18, 2026

Last Modified

November 10, 2026

Advisory Details (4)

Auto-updated May 13, 2026
Patch available. Sources: github.
Web pageMentions a patch (unverified)

[SECURITY] [DLA 4581-1] nghttp2 security update

https://lists.debian.org/debian-lts-announce/2026/05/msg00025.html
Web page

oss-security - nghttp2 Denial of service: Assertion failure due to the missing state validation

http://www.openwall.com/lists/oss-security/2026/03/20/3
GitHub advisoryMentions a patch (unverified)

Denial of service: Assertion failure due to the missing state validation · Advisory · nghttp2/nghttp2 · GitHub

https://github.com/nghttp2/nghttp2/security/advisories/GHSA-6933-cjhr-5qg6
Web page

Fix missing iframe->state validations to avoid assertion failure · nghttp2/nghttp2@5c7df8f · GitHub

https://github.com/nghttp2/nghttp2/commit/5c7df8fa815ac1004d9ecb9d1f7595c4d37f46e1

Patch Availability(30)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatcert-manager/cert-manager-operator-bundle:17919662592026-10-14redhat
redhatcert-manager/cert-manager-operator-bundle:17919704842026-10-14redhat
redhatcert-manager/cert-manager-operator-rhel9:17890290762026-10-13redhat
redhatcert-manager/cert-manager-istio-csr-rhel9:17914597592026-10-13redhat
redhatcert-manager/cert-manager-operator-rhel9:17917882872026-10-13redhat
redhatcert-manager/jetstack-cert-manager-rhel9:17913710692026-10-13redhat
redhatcert-manager/jetstack-cert-manager-rhel9:17914597112026-10-13redhat
redhatnghttp2-main-1.69.0-6.1.hum12026-10-07redhat
redhatnghttp22026-06-22redhat
redhatjbcs-httpd24-nghttp2-0:1.64.0-3.el7jbcs2026-06-22redhat
redhatrhaiis/model-opt-cuda-rhel9:17806819842026-06-10redhat
redhatopenshift/ose-rhel-coreos-8:412.86.202605271418-02026-06-04redhat
redhatopenshift/ose-rhel-coreos-9:413.92.202605271328-02026-06-04redhat
redhatopenshift/ose-rhel-coreos-9:418.94.202605260517-02026-06-03redhat
redhatopenshift/ose-rhel-coreos-9:416.94.202605200242-02026-05-29redhat
redhatopenshift/ose-rhel-coreos-9:4.19.9.6.202605201155-02026-05-27redhat
redhatrhaiis/vllm-cuda-rhel9:17792236542026-05-20redhat
redhatrhaiis/vllm-rocm-rhel9:17792236512026-05-20redhat
redhatopenshift/ose-rhel-coreos-9:417.94.202605112123-02026-05-20redhat
redhatopenshift/ose-rhel-coreos-9:414.92.202605060243-02026-05-13redhat
redhatopenshift/ose-rhel-coreos-9:415.92.202605060220-02026-05-13redhat
redhatrhaiis/vllm-spyre-rhel9:17782445462026-05-12redhat
redhatrhaiis/vllm-rocm-rhel9:17782445312026-05-11redhat
redhatrhaiis/vllm-cuda-rhel9:17782746662026-05-11redhat
redhatrhaiis/model-opt-cuda-rhel9:17782445592026-05-11redhat
redhatdiscovery/discovery-ui-rhel9:17781567562026-05-07redhat
redhatrhpam-7/rhpam-smartrouter-rhel8:7.13.5-4.17773257082026-05-05redhat
redhatrhui5/rhua-tp-rhel9:17774595042026-04-29redhat
redhatrhui5/rhua-rhel9:17768688422026-04-23redhat
redhatnodejs:20-9040020260421133644.rhel92026-04-22redhat

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

(8 across 8 ecosystems)
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
nghttp2—
  • every version up to 1.68.1: fixed in 1.68.1
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
nghttp2—
  • every version up to 1.68.1: fixed in 1.68.1
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
nghttp2—
  • every version up to 1.68.1: fixed in 1.68.1
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
nghttp2—
  • every version up to 1.68.1-r0: fixed in 1.68.1-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
nghttp21.43.0-1, 1.43.0-1+deb11u1, 1.43.0-1+deb11u2
  • every version up to 1.43.0-1+deb11u3: fixed in 1.43.0-1+deb11u3
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
nghttp21.52.0-1, 1.52.0-1+deb12u1, 1.52.0-1+deb12u2
  • every version up to 1.52.0-1+deb12u3: fixed in 1.52.0-1+deb12u3
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
nghttp21.64.0-1.1
  • every version up to 1.64.0-1.1+deb13u1: fixed in 1.64.0-1.1+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
nghttp21.64.0-1.1, 1.68.0-1, 1.68.0-2
  • every version up to 1.68.1-1: fixed in 1.68.1-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(13)

Data Freshness Timeline

(refreshed 8× in last 7d / 35× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 283 rows on record for this CVE, as 97 entries (3 repeats merged).

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. 3 repeat rows among the latest 100 are merged into the row they repeat. The 183 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:51 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  2. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  3. 2026-11-11 16:39 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  4. 2026-11-10 16:43 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  5. 2026-11-10 13:27 UTCEchelonGraph re-scored
  6. 2026-11-10 13:27 UTCVendor advisory
  7. 2026-11-10 12:50 UTCEchelonGraph re-scored
  8. 2026-11-09 16:34 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  9. 2026-11-08 16:38 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  10. 2026-11-07 16:38 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  11. 2026-11-06 16:37 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  12. 2026-11-06 03:19 UTCEchelonGraph re-scored
  13. 2026-11-06 03:19 UTCVendor advisory
  14. 2026-11-05 16:37 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  15. 2026-11-04 16:35 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  16. 2026-11-03 16:47 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  17. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  18. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  19. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  20. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  21. 2026-10-29 19:05 UTCEchelonGraph re-scored
  22. 2026-10-29 19:05 UTCVendor advisory
  23. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  24. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  25. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.8% · 56th percentile
Show 72 more
  1. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  2. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  3. 2026-10-25 14:39 UTCEchelonGraph re-scored
  4. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  5. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  6. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  7. 2026-10-22 10:51 UTCEchelonGraph re-scored
  8. 2026-10-22 10:51 UTCVendor advisory
  9. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  10. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  11. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  12. 2026-10-18 03:51 UTCEchelonGraph re-scored
  13. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  14. 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  15. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  16. 2026-10-15 02:36 UTCEchelonGraph re-scored
  17. 2026-10-15 02:36 UTCVendor advisory
  18. 2026-10-15 01:40 UTCEchelonGraph re-scored
  19. 2026-10-15 01:40 UTCVendor advisory
  20. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  21. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  22. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  23. 2026-10-12 16:17 UTCEchelonGraph re-scored
  24. 2026-10-11 20:00 UTCEchelonGraph re-scored
  25. 2026-10-11 17:13 UTCEchelonGraph re-scored
  26. 2026-10-11 14:44 UTCEchelonGraph re-scored
  27. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  28. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  29. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  30. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  31. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  32. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  33. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  34. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  35. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  36. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  37. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  38. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  39. 2026-09-28 01:19 UTCOSV refresh
  40. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  41. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  42. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  43. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  44. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  45. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  46. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  47. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  48. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  49. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  50. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  51. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  52. 2026-09-08 09:18 UTCEchelonGraph re-scored
  53. 2026-09-08 09:18 UTCVendor advisory
  54. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  55. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  56. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  57. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  58. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  59. 2026-09-01 12:24 UTCEchelonGraph re-scored
  60. 2026-09-01 12:24 UTCVendor advisory
  61. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  62. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  63. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  64. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  65. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  66. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  67. 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  68. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  69. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  70. 2026-08-21 12:32 UTCEchelonGraph re-scored
  71. 2026-08-21 12:32 UTCVendor advisory
  72. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.8% · 53rd percentile

Frequently asked(5)

What is CVE-2026-27135?
CVE-2026-27135 is a high-severity vulnerability; its CVE record was published on March 18, 2026. nghttp2 is an implementation of the Hypertext Transfer Protocol version 2 in C. Prior to version 1.68.1, the nghttp2 library stops reading the incoming data when user facing public API nghttp2_session_terminate_session or nghttp2_session_terminate_session2 is called by the application. They might…
When was the CVE record for CVE-2026-27135 published?
The CVE record for CVE-2026-27135 was published on March 18, 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 November 10, 2026; the record at its source may have been updated since.
Is CVE-2026-27135 actively exploited?
CVE-2026-27135 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.9% probability of exploitation in the next 30 days (59th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-27135?
CVE-2026-27135 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-27135?
A fix for CVE-2026-27135 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-27135 are linked in the Vendor Advisories panel on this page.

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