CVE-2026-61674

CRITICALPre-NVD 9.29.2
EchelonGraph scoreMEDIUM confidence

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

This critical-severity CVE scores 9.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.7% (54th 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
Trending — 4 sources updated this weekElevated

Also known asEUVD-2026-83985 (ENISA EUVD)Source: ENISA EUVD

9.2EG
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).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 9.2Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

Fluent Bit is a fast and lightweight logs, metrics, and traces processor for Linux, BSD, macOS, and Windows. From 0.11.0 until 5.0.8, plugins/out_forward/forward.c secure_forward_pong copies the server-controlled PONG[2] reason into the 32-byte stack buffer msg with memcpy without checking its MessagePack type or length. An attacker who controls or can impersonate an out_forward Secure Forward destination configured with Shared_Key or Empty_Shared_Key can send an oversized reason during the first handshake and overwrite stack control data. Protected builds reliably terminate, while builds without a stack canary or with a disclosure can allow remote code execution as the Fluent Bit process user. When the opt-in --supervisor mode is used, fork-only respawns preserve the canary and address layout, allowing repeated crash-or-survive probes to support code execution on a hardened build; ordinary exec-based or service-manager restarts do not preserve that state. This issue is fixed in version 5.0.8.

CVSS v3
9.2
EG Score
9.2CRITICALmedium confidence
EG Risk
57
EG Risk 57/100

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)
Severity92% × 45%
Impact severity (EG Severity): CVSS 9.2 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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
0.7%
EPSS %ILE
54th
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 (9.2): severity, escalated by confirmed exploitation. This CVE's 9.2 is its impact severity (EG Severity), not escalated.

EG Severity
9.2 CRITICALCVSS-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
0.7% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-09). 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, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 14 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 low, Track* at medium and Attend at high mission impact.

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

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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; 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 total (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

September 21, 2026

Last Modified

September 24, 2026

Advisory Details (4)

Auto-updated Sep 21, 2026
Patch available. Sources: github, github_pr, github_commit, github_release.
GitHub release Patch Available

Fluent Bit 5.0.8

Patch available: fluent/fluent-bit v5.0.8

https://github.com/fluent/fluent-bit/releases/tag/v5.0.8
GitHub commit Patch Available

commit 45486556be9d (fluent/fluent-bit)

Patch available: fluent/fluent-bit v5.0.8 (contains commit 45486556be9d)

https://github.com/fluent/fluent-bit/commit/45486556be9d023e194665e243f156b228e195e0
GitHub pull request Patch Available

out_forward: process type and length of pong strictly

Patch available: fluent/fluent-bit v5.0.8 (PR #11945 merged 2026-06-15)

https://github.com/fluent/fluent-bit/pull/11945
GitHub advisoryMentions a patch (unverified)

Remote stack buffer overflow in Fluent Bit `out_forward` Secure-Forward `PONG` handler · Advisory · fluent/fluent-bit · GitHub

https://github.com/fluent/fluent-bit/security/advisories/GHSA-jrp8-r9hx-gf73

Vendor Advisories for CVE-2026-61674(1)

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

Weakness Classification(3)

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

Data Freshness Timeline

(refreshed 22× in last 7d / 91× 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 188 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 88 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-09 22:38 UTCEG score recompute
  2. 2026-11-09 16:35 UTCEPSS rescoreEPSS 0.7% · 54th percentile
  3. 2026-11-09 00:58 UTCEG score recompute
  4. 2026-11-09 00:58 UTCVendor advisory
  5. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.7% · 54th percentile
  6. 2026-11-08 03:18 UTCEG score recompute
  7. 2026-11-08 03:18 UTCVendor advisory
  8. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.7% · 54th percentile
  9. 2026-11-07 05:37 UTCEG score recompute
  10. 2026-11-07 05:37 UTCVendor advisory
  11. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.7% · 54th percentile
  12. 2026-11-06 14:25 UTCOSV refresh
  13. 2026-11-06 07:57 UTCEG score recompute
  14. 2026-11-06 07:57 UTCVendor advisory
  15. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.7% · 54th percentile
  16. 2026-11-05 10:16 UTCEG score recompute
  17. 2026-11-05 10:16 UTCVendor advisory
  18. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.7% · 54th percentile
  19. 2026-11-04 12:31 UTCEG score recompute
  20. 2026-11-04 12:31 UTCVendor advisory
  21. 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  22. 2026-11-03 14:50 UTCVendor advisory
  23. 2026-11-02 16:58 UTCEG score recompute
  24. 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  25. 2026-11-01 19:18 UTCEG score recompute
Show 75 more
  1. 2026-11-01 19:18 UTCVendor advisory
  2. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  3. 2026-10-31 21:37 UTCEG score recompute
  4. 2026-10-31 21:37 UTCVendor advisory
  5. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  6. 2026-10-30 23:57 UTCEG score recompute
  7. 2026-10-30 23:57 UTCVendor advisory
  8. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  9. 2026-10-30 02:17 UTCEG score recompute
  10. 2026-10-30 02:17 UTCVendor advisory
  11. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  12. 2026-10-29 04:37 UTCEG score recompute
  13. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  14. 2026-10-28 06:46 UTCEG score recompute
  15. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  16. 2026-10-27 09:06 UTCEG score recompute
  17. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  18. 2026-10-26 10:28 UTCEG score recompute
  19. 2026-10-26 10:28 UTCVendor advisory
  20. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  21. 2026-10-25 14:14 UTCEG score recompute
  22. 2026-10-25 12:48 UTCEG score recompute
  23. 2026-10-25 12:48 UTCVendor advisory
  24. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  25. 2026-10-24 15:05 UTCVendor advisory
  26. 2026-10-23 17:25 UTCEG score recompute
  27. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  28. 2026-10-22 19:45 UTCEG score recompute
  29. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  30. 2026-10-21 22:05 UTCEG score recompute
  31. 2026-10-21 22:05 UTCVendor advisory
  32. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  33. 2026-10-21 00:00 UTCEG score recompute
  34. 2026-10-21 00:00 UTCVendor advisory
  35. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  36. 2026-10-20 02:16 UTCEG score recompute
  37. 2026-10-20 02:16 UTCVendor advisory
  38. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  39. 2026-10-19 01:37 UTCEG score recompute
  40. 2026-10-19 01:37 UTCVendor advisory
  41. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  42. 2026-10-18 03:56 UTCVendor advisory
  43. 2026-10-18 03:25 UTCEG score recompute
  44. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  45. 2026-10-17 06:12 UTCEG score recompute
  46. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  47. 2026-10-16 07:18 UTCEG score recompute
  48. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  49. 2026-10-15 06:13 UTCEG score recompute
  50. 2026-10-15 06:13 UTCVendor advisory
  51. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  52. 2026-10-14 01:50 UTCEG score recompute
  53. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  54. 2026-10-12 22:05 UTCEG score recompute
  55. 2026-10-12 22:05 UTCVendor advisory
  56. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  57. 2026-10-12 15:50 UTCEG score recompute
  58. 2026-10-12 04:47 UTCVendor advisory
  59. 2026-10-11 22:59 UTCVendor advisory
  60. 2026-10-11 19:34 UTCEG score recompute
  61. 2026-10-11 18:54 UTCVendor advisory
  62. 2026-10-11 16:49 UTCEG score recompute
  63. 2026-10-11 14:56 UTCVendor advisory
  64. 2026-10-11 14:11 UTCEG score recompute
  65. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  66. 2026-10-11 10:58 UTCVendor advisory
  67. 2026-10-11 06:42 UTCVendor advisory
  68. 2026-10-11 02:44 UTCVendor advisory
  69. 2026-10-10 21:55 UTCEG score recompute
  70. 2026-10-10 21:55 UTCVendor advisory
  71. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  72. 2026-10-10 13:40 UTCVendor advisory
  73. 2026-10-10 09:43 UTCVendor advisory
  74. 2026-10-10 05:43 UTCVendor advisory
  75. 2026-10-10 01:47 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-61674?
CVE-2026-61674 is a critical-severity vulnerability; its CVE record was published on September 21, 2026. Fluent Bit is a fast and lightweight logs, metrics, and traces processor for Linux, BSD, macOS, and Windows. From 0.11.0 until 5.0.8, plugins/out_forward/forward.c secure_forward_pong copies the server-controlled PONG[2] reason into the 32-byte stack buffer msg with memcpy without checking its…
When was the CVE record for CVE-2026-61674 published?
The CVE record for CVE-2026-61674 was published on September 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 24, 2026; the record at its source may have been updated since.
Is CVE-2026-61674 actively exploited?
CVE-2026-61674 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (54th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-61674?
CVE-2026-61674 has a CVSS base score of 9.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-61674?
A fix for CVE-2026-61674 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-61674 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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