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% (53rd 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 — 3 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
53rd
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 2026-11-01). 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 18× in last 7d / 128× 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 164 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 64 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

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

Related CVEs(same CWE)

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 (53rd 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.

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