CVE-2026-55841

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: 0.6% (48th 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
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: 0.6%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Graylog is a free and open log management platform. Prior to Graylog Server versions 6.3.12, 7.0.7, and 7.1.2 and Graylog Forwarder version 7.3, the FortiGate key-value syslog parser in graylog2-server/src/main/java/org/graylog2/inputs/codecs/GLFortiGateSyslogEvent.java and graylog2-server/src/main/java/org/graylog2/inputs/codecs/SyslogCodec.java mishandles field-like text inside quoted values. GLFortiGateSyslogEvent.getFields() uses KV_PATTERN and QUOTED_KV_PATTERN, while SyslogCodec.parse() invokes the FortiGateSyslogEvent parser; crafted values containing = or backslash-escaped quotes can cause embedded keys such as srcip, dstip, date, time, and tz to remove or overwrite original top-level fields or produce an invalid message that Graylog discards. An unauthenticated network sender who can submit syslog messages can therefore manipulate security-log fields or evade logging to obscure malicious activity. This issue is fixed in Graylog Server versions 6.3.12, 7.0.7, and 7.1.2 and Graylog Forwarder version 7.3.

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 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 (value × EchelonGraph’s weight)
Severity75% × 45%
The EG Score, 7.5 of 10.
Exploitation0.6% × 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
0.6%
EPSS %ILE
48th
KEV
Not listed

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.

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

August 28, 2026

Last Modified

September 9, 2026

Advisory Details (9)

Auto-updated Aug 28, 2026
Patch available. Sources: github, github_pr, github_commit.
GitHub commit

commit dde76d7432c4 (Graylog2/graylog2-server)

Fix landed in Graylog2/graylog2-server commit dde76d7432c4 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/commit/dde76d7432c469887d9a95c208083c5f0f73c70d
GitHub commit

commit d5051e604c96 (Graylog2/graylog2-server)

Fix landed in Graylog2/graylog2-server commit d5051e604c96 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/commit/d5051e604c962ef3d4e5e8e434d0ff4907d2140d
GitHub commit

commit 85dc699d6319 (Graylog2/graylog2-server)

Fix landed in Graylog2/graylog2-server commit 85dc699d6319 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/commit/85dc699d6319aea433583dc239077a3a799c8627
GitHub commit

commit 793df6e8202e (Graylog2/graylog2-server)

Fix landed in Graylog2/graylog2-server commit 793df6e8202e — awaiting tagged release

https://github.com/Graylog2/graylog2-server/commit/793df6e8202ea55c15a762e47a2a8a775961dd3f
GitHub pull request

Fix FortiGate syslog parser handling of quoted values (`6.3`)

Fix merged in Graylog2/graylog2-server PR #26059 on 2026-05-19 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/pull/26059
GitHub pull request

Fix FortiGate syslog parser handling of quoted values (`7.0`)

Fix merged in Graylog2/graylog2-server PR #26057 on 2026-05-19 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/pull/26057
GitHub pull request

Fix FortiGate syslog parser handling of quoted values (`7.1`)

Fix merged in Graylog2/graylog2-server PR #26056 on 2026-05-19 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/pull/26056
GitHub pull request

Fix FortiGate syslog parser handling of quoted values

Fix merged in Graylog2/graylog2-server PR #26050 on 2026-05-19 — awaiting tagged release

https://github.com/Graylog2/graylog2-server/pull/26050
GitHub advisoryMentions a patch (unverified)

Fortigate syslog message parser can be exploited to modify or delete fields from the original message · Advisory · Graylog2/graylog2-server · GitHub

https://github.com/Graylog2/graylog2-server/security/advisories/GHSA-gqr6-r77p-c2pj

Vendor Advisories for CVE-2026-55841(1)

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

Affected Packages

(1 across 1 ecosystem)
Maven(1)
PackageVulnerable rangeFix by version rangeDependents
org.graylog2:graylog2-server7.1.1
  • every version up to 6.3.12: fixed in 6.3.12
  • 7.0.0 up to 7.0.7: fixed in 7.0.7
  • 7.1.0 up to 7.1.2: fixed in 7.1.2
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 56× 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.

  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  3. 2026-10-12 15:55 UTCEG score recompute
  4. 2026-10-11 19:38 UTCEG score recompute
  5. 2026-10-11 16:53 UTCEG score recompute
  6. 2026-10-11 14:16 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  9. 2026-10-10 00:47 UTCEG score recompute
  10. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  11. 2026-10-09 02:36 UTCEG score recompute
  12. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  13. 2026-10-08 00:47 UTCEG score recompute
  14. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  15. 2026-10-06 20:27 UTCEG score recompute
  16. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  17. 2026-10-06 07:27 UTCEG score recompute
  18. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  19. 2026-10-05 04:29 UTCEG score recompute
  20. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  21. 2026-10-04 02:27 UTCEG score recompute
  22. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  23. 2026-10-02 22:58 UTCEG score recompute
  24. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  25. 2026-10-01 21:22 UTCEG score recompute
Show 63 more
  1. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  2. 2026-09-30 19:48 UTCEG score recompute
  3. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  4. 2026-09-30 03:48 UTCEG score recompute
  5. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  6. 2026-09-29 00:03 UTCEG score recompute
  7. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  8. 2026-09-27 22:29 UTCEG score recompute
  9. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  10. 2026-09-26 20:55 UTCEG score recompute
  11. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  12. 2026-09-26 08:02 UTCEG score recompute
  13. 2026-09-24 22:07 UTCEG score recompute
  14. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  15. 2026-09-23 19:51 UTCEG score recompute
  16. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  17. 2026-09-22 18:17 UTCEG score recompute
  18. 2026-09-22 03:59 UTCEG score recompute
  19. 2026-09-21 02:25 UTCEG score recompute
  20. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  21. 2026-09-20 00:50 UTCEG score recompute
  22. 2026-09-18 23:14 UTCEG score recompute
  23. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  24. 2026-09-17 21:39 UTCEG score recompute
  25. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  26. 2026-09-16 20:03 UTCEG score recompute
  27. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  28. 2026-09-16 07:16 UTCEG score recompute
  29. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  30. 2026-09-15 05:36 UTCEG score recompute
  31. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  32. 2026-09-14 03:45 UTCEG score recompute
  33. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  34. 2026-09-13 02:11 UTCEG score recompute
  35. 2026-09-12 00:35 UTCEG score recompute
  36. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  37. 2026-09-11 11:48 UTCEG score recompute
  38. 2026-09-10 09:58 UTCEG score recompute
  39. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  40. 2026-09-09 00:25 UTCEG score recompute
  41. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  42. 2026-09-08 04:33 UTCEG score recompute
  43. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  44. 2026-09-06 14:09 UTCEG score recompute
  45. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  46. 2026-09-06 01:22 UTCEG score recompute
  47. 2026-09-04 23:46 UTCEG score recompute
  48. 2026-09-04 10:59 UTCEG score recompute
  49. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  50. 2026-09-02 20:23 UTCEG score recompute
  51. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  52. 2026-09-01 16:19 UTCEG score recompute
  53. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  54. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  55. 2026-09-01 03:33 UTCEG score recompute
  56. 2026-09-01 02:41 UTCEG score recompute
  57. 2026-08-31 02:38 UTCEG score recompute
  58. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  59. 2026-08-30 13:52 UTCEG score recompute
  60. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  61. 2026-08-28 23:25 UTCEG score recompute
  62. 2026-08-28 22:22 UTCEG score recomputeFirst assessed: 7.5 HIGH
  63. 2026-08-28 22:18 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-55841?
CVE-2026-55841 is a high-severity vulnerability; its CVE record was published on August 28, 2026. Graylog is a free and open log management platform. Prior to Graylog Server versions 6.3.12, 7.0.7, and 7.1.2 and Graylog Forwarder version 7.3, the FortiGate key-value syslog parser in graylog2-server/src/main/java/org/graylog2/inputs/codecs/GLFortiGateSyslogEvent.java and…
When was the CVE record for CVE-2026-55841 published?
The CVE record for CVE-2026-55841 was published on August 28, 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 9, 2026; the record at its source may have been updated since.
Is CVE-2026-55841 actively exploited?
CVE-2026-55841 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (48th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55841?
CVE-2026-55841 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-2026-55841?
A fix for CVE-2026-55841 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-55841 are linked in the Vendor Advisories panel on this page.

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