CVE-2024-30255

CRITICALNVD 5.39.0
EchelonGraph scoreHIGH confidence

“▲” beside the score: it is higher than NVD's CVSS score.

Score elevated to 9.0 because EPSS predicted 85% probability of exploitation within the next 30 days (99th percentile of EPSS-scored CVEs) when EchelonGraph scored this CVE. NVD baseline CVSS 5.3 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction (continuous uplift above 30%)
Sources: EPSS, NVD CVSS v3
Elevated

Also known asEUVD-2024-28182 (ENISA EUVD)Source: ENISA EUVD

9.0EG
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 exploitation likelihood — EPSS 85%
  • Public exploit or proof-of-concept code is available
CISA-KEV: Not listedEPSS PROB: 85%CVSS: 5.3Exploit: Public PoCExposed services: Not assessed

A fix is available — apply it.

Envoy is a cloud-native, open source edge and service proxy. The HTTP/2 protocol stack in Envoy versions prior to 1.29.3, 1.28.2, 1.27.4, and 1.26.8 are vulnerable to CPU exhaustion due to flood of CONTINUATION frames. Envoy's HTTP/2 codec allows the client to send an unlimited number of CONTINUATION frames even after exceeding Envoy's header map limits. This allows an attacker to send a sequence of CONTINUATION frames without the END_HEADERS bit set causing CPU utilization, consuming approximately 1 core per 300Mbit/s of traffic and culminating in denial of service through CPU exhaustion. Users should upgrade to version 1.29.3, 1.28.2, 1.27.4, or 1.26.8 to mitigate the effects of the CONTINUATION flood. As a workaround, disable HTTP/2 protocol for downstream connections.

CVSS v3
5.3
EG Score
9.0CRITICALhigh confidence
EG Risk
73
EG Risk 73/100

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)
Severity53% × 45%
Impact severity (EG Severity): CVSS 5.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation85% × 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
85%
EPSS %ILE
99th
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 (9.0): severity, escalated by confirmed exploitation. This CVE's 9.0 is EPSS's lift toward 9.0 from its impact severity (EG Severity, CVSS 5.3 MEDIUM): a likelihood of exploitation, not impact.

EG Severity
5.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
85% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). 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

April 4, 2024

Last Modified

November 4, 2025

Advisory Details (4)

Auto-updated Oct 16, 2026
Patch available. Sources: cert, github.
CERT

VU#421644 - HTTP/2 CONTINUATION frames can be utilized for DoS attacks

https://www.kb.cert.org/vuls/id/421644
GitHub advisoryMentions a patch (unverified)

HTTP/2: CPU exhaustion due to CONTINUATION frame flood · Advisory · envoyproxy/envoy · GitHub

https://github.com/envoyproxy/envoy/security/advisories/GHSA-j654-3ccm-vfmm
Web page

oss-security - Envoy security releases [1.29.3, 1.28.2, 1.27.4, 1.26.8] are now available

http://www.openwall.com/lists/oss-security/2024/04/05/3
Web page

oss-security - CERT/CC VU#421644: HTTP/2 CONTINUATION frames can be utilized for DoS attacks

http://www.openwall.com/lists/oss-security/2024/04/03/16

Patch Availability(4)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatrhceph/snmp-notifier-rhel9:1.2.1-922025-02-24redhat
redhatrhceph/snmp-notifier-rhel8:1.2.1-882025-02-13redhat
redhatopenshift-service-mesh/ratelimit-rhel8:2.5.5-32024-10-07redhat
redhatrhmtc/openshift-migration-velero-plugin-for-gcp-rhel8:v1.7.16-62024-07-11redhat

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.

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 10× in last 7d / 42× 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 161 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 61 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 00:52 UTCEchelonGraph re-scored
  2. 2026-11-13 00:52 UTCVendor advisory
  3. 2026-11-12 16:31 UTCEPSS rescoreEPSS 85% · 99th percentile
  4. 2026-11-11 23:07 UTCEchelonGraph re-scored
  5. 2026-11-11 23:07 UTCVendor advisory
  6. 2026-11-11 16:34 UTCEPSS rescoreEPSS 85% · 99th percentile
  7. 2026-11-10 21:22 UTCEchelonGraph re-scored
  8. 2026-11-10 21:22 UTCVendor advisory
  9. 2026-11-10 16:38 UTCEPSS rescoreEPSS 85% · 99th percentile
  10. 2026-11-09 19:36 UTCEchelonGraph re-scored
  11. 2026-11-09 19:36 UTCVendor advisory
  12. 2026-11-08 17:51 UTCEchelonGraph re-scored
  13. 2026-11-08 17:51 UTCVendor advisory
  14. 2026-11-08 16:36 UTCEPSS rescoreEPSS 85% · 99th percentile
  15. 2026-11-07 16:05 UTCEchelonGraph re-scored
  16. 2026-11-07 16:05 UTCVendor advisory
  17. 2026-11-06 14:18 UTCEchelonGraph re-scored
  18. 2026-11-06 14:18 UTCVendor advisory
  19. 2026-11-05 12:33 UTCEchelonGraph re-scored
  20. 2026-11-05 12:33 UTCVendor advisory
  21. 2026-11-04 23:25 UTCOSV refresh
  22. 2026-11-04 16:32 UTCEPSS rescoreEPSS 85% · 99th percentile
  23. 2026-11-04 10:48 UTCEchelonGraph re-scored
  24. 2026-11-04 10:48 UTCVendor advisory
  25. 2026-11-03 09:02 UTCEchelonGraph re-scored
Show 72 more
  1. 2026-11-03 09:02 UTCVendor advisory
  2. 2026-11-02 07:16 UTCEchelonGraph re-scored
  3. 2026-11-02 07:16 UTCVendor advisory
  4. 2026-11-01 05:31 UTCEchelonGraph re-scored
  5. 2026-11-01 05:31 UTCVendor advisory
  6. 2026-10-31 16:30 UTCEPSS rescoreEPSS 88% · 99th percentile
  7. 2026-10-31 03:45 UTCEchelonGraph re-scored
  8. 2026-10-31 03:45 UTCVendor advisory
  9. 2026-10-30 02:00 UTCEchelonGraph re-scored
  10. 2026-10-30 02:00 UTCVendor advisory
  11. 2026-10-29 16:30 UTCEPSS rescoreEPSS 88% · 99th percentile
  12. 2026-10-29 00:15 UTCEchelonGraph re-scored
  13. 2026-10-29 00:15 UTCVendor advisory
  14. 2026-10-27 22:30 UTCEchelonGraph re-scored
  15. 2026-10-27 22:30 UTCVendor advisory
  16. 2026-10-26 20:41 UTCEchelonGraph re-scored
  17. 2026-10-26 20:41 UTCVendor advisory
  18. 2026-10-25 17:01 UTCEchelonGraph re-scored
  19. 2026-10-25 17:01 UTCVendor advisory
  20. 2026-10-25 16:30 UTCEPSS rescoreEPSS 88% · 99th percentile
  21. 2026-10-24 15:15 UTCEchelonGraph re-scored
  22. 2026-10-24 15:15 UTCVendor advisory
  23. 2026-10-23 16:29 UTCEPSS rescoreEPSS 88% · 99th percentile
  24. 2026-10-23 13:30 UTCEchelonGraph re-scored
  25. 2026-10-23 13:30 UTCVendor advisory
  26. 2026-10-22 16:31 UTCEPSS rescoreEPSS 88% · 99th percentile
  27. 2026-10-22 11:44 UTCEchelonGraph re-scored
  28. 2026-10-22 11:44 UTCVendor advisory
  29. 2026-10-21 16:29 UTCEPSS rescoreEPSS 88% · 99th percentile
  30. 2026-10-21 09:57 UTCEchelonGraph re-scored
  31. 2026-10-21 09:57 UTCVendor advisory
  32. 2026-10-20 08:11 UTCEchelonGraph re-scored
  33. 2026-10-20 08:11 UTCVendor advisory
  34. 2026-10-19 16:29 UTCEPSS rescoreEPSS 88% · 99th percentile
  35. 2026-10-19 06:26 UTCEchelonGraph re-scored
  36. 2026-10-19 06:26 UTCVendor advisory
  37. 2026-10-18 04:40 UTCEchelonGraph re-scored
  38. 2026-10-18 04:40 UTCVendor advisory
  39. 2026-10-17 02:53 UTCEchelonGraph re-scored
  40. 2026-10-17 02:53 UTCVendor advisory
  41. 2026-10-16 01:07 UTCEchelonGraph re-scored
  42. 2026-10-16 01:07 UTCVendor advisory
  43. 2026-10-14 20:10 UTCEchelonGraph re-scored
  44. 2026-10-14 20:10 UTCVendor advisory
  45. 2026-10-14 16:30 UTCEPSS rescoreEPSS 88% · 99th percentile
  46. 2026-10-13 16:30 UTCEPSS rescoreEPSS 88% · 99th percentile
  47. 2026-10-13 16:17 UTCVendor advisory
  48. 2026-10-12 17:57 UTCEchelonGraph re-scored
  49. 2026-10-12 14:29 UTCEchelonGraph re-scored
  50. 2026-10-12 14:29 UTCVendor advisory
  51. 2026-10-11 21:21 UTCEchelonGraph re-scored
  52. 2026-10-11 16:24 UTCOSV refresh
  53. 2026-10-11 16:14 UTCEchelonGraph re-scored
  54. 2026-10-06 15:15 UTCEPSS rescoreEPSS 88% · 99th percentile
  55. 2026-10-01 19:48 UTCEPSS rescoreEPSS 88% · 99th percentile
  56. 2026-09-30 19:42 UTCEchelonGraph re-scored
  57. 2026-09-24 14:01 UTCEPSS rescoreEPSS 88% · 99th percentile
  58. 2026-09-23 13:46 UTCEPSS rescoreEPSS 88% · 99th percentile
  59. 2026-09-22 14:46 UTCEPSS rescoreEPSS 88% · 99th percentile
  60. 2026-09-22 03:46 UTCOSV refresh
  61. 2026-09-18 19:26 UTCEPSS rescoreEPSS 88% · 99th percentile
  62. 2026-09-16 14:06 UTCEPSS rescoreEPSS 88% · 99th percentile
  63. 2026-09-11 09:35 UTCEPSS rescoreEPSS 88% · 99th percentile
  64. 2026-09-07 15:59 UTCEPSS rescoreEPSS 88% · 99th percentile
  65. 2026-09-06 13:46 UTCEPSS rescoreEPSS 88% · 99th percentile
  66. 2026-09-05 15:26 UTCEPSS rescoreEPSS 88% · 99th percentile
  67. 2026-09-04 13:58 UTCEPSS rescoreEPSS 88% · 99th percentile
  68. 2026-09-04 05:05 UTCEPSS rescoreEPSS 88% · 99th percentile
  69. 2026-09-03 01:29 UTCOSV refresh
  70. 2026-08-30 19:15 UTCEPSS rescoreEPSS 88% · 99th percentile
  71. 2026-08-28 21:39 UTCEPSS rescoreEPSS 88% · 99th percentile
  72. 2026-08-26 14:44 UTCEPSS rescoreEPSS 88% · 99th percentile

Publicly available exploits

(1 reference)

Public exploit code is referenced for this CVE (1 GitHub PoC). Defenders should treat patch urgency accordingly.

  • GitHub PoCblackmagic2023/Envoy-CPU-Exhaustion-Vulnerability-PoC
    Published Apr 9, 2024

    CVE-2024-30255 This repository contains a proof-of-concept (PoC) Python script to demonstrate the CPU exhaustion vulnerability in Envoy caused by a flood of CONTINUATION frames.

    Open source ↗

Frequently asked(5)

What is CVE-2024-30255?
CVE-2024-30255 is a critical-severity vulnerability; its CVE record was published on April 4, 2024. Envoy is a cloud-native, open source edge and service proxy. The HTTP/2 protocol stack in Envoy versions prior to 1.29.3, 1.28.2, 1.27.4, and 1.26.8 are vulnerable to CPU exhaustion due to flood of CONTINUATION frames. Envoy's HTTP/2 codec allows the client to send an unlimited number of…
When was the CVE record for CVE-2024-30255 published?
The CVE record for CVE-2024-30255 was published on April 4, 2024. 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 4, 2025; the record at its source may have been updated since.
Is CVE-2024-30255 actively exploited?
CVE-2024-30255 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 85% probability of exploitation in the next 30 days (99th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2024-30255?
CVE-2024-30255 has a CVSS v3 base score of 5.3 (NVD). EchelonGraph synthesises NVD + FIRST EPSS into a combined EG score of 9.0 (CRITICAL).
How do I remediate CVE-2024-30255?
A fix for CVE-2024-30255 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2024-30255 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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