CVE-2026-77261

HIGHNVD 8.58.5
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 8.5 under NVD CVSS v3. EPSS exploit probability: 0.4% (31st percentile of EPSS-scored CVEs). GitHub Security Advisory CVSS 7.1 is lower than this score; a lower GitHub score revises it only when its advisory is newer than the CVE record's last change, and this advisory (published 2026-09-22) is not newer than that change (2026-09-25), so it does not.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3

Also known asEUVD-2026-84631 (ENISA EUVD) · GHSA-6529-c226-h328 (GitHub Security Advisories) · PYSEC-2026-4085 (OSV.dev)Source: ENISA EUVD

8.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 8.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, _make_ssrf_safe_hook is omitted from JiraFetcher and ConfluenceFetcher sessions created through the basic-auth and oauth_pat branches. If an attacker-controlled or compromised configured Atlassian instance returns a redirect to an internal address, those sessions can follow the redirect without revalidating its destination. This issue is fixed in version 0.22.0.

CVSS v3
8.5
EG Score
8.5HIGHmedium confidence
EG Risk
38
EG Risk 38/100

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)
Severity85% × 45%
Impact severity (EG Severity): CVSS 8.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (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.
EPSS PROB
0.4%
EPSS %ILE
31st
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 (8.5): severity, escalated by confirmed exploitation. This CVE's 8.5 is its impact severity (EG Severity), not escalated.

EG Severity
8.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.4% 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 every mission impact level.CISA BOD 26-04: 60 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 every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (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)60 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 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

September 22, 2026

Last Modified

September 25, 2026

Advisory Details (4)

Auto-updated Sep 22, 2026
Patch available. Sources: github, github_pr, github_commit, github_release.
GitHub release Patch Available

v0.22.0

Patch available: sooperset/mcp-atlassian v0.22.0

https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0
GitHub commit Patch Available

commit b041733473f9 (sooperset/mcp-atlassian)

Patch available: sooperset/mcp-atlassian v0.22.0 (contains commit b041733473f9)

https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460
GitHub pull request Patch Available

Security hardening across attachment, transport, SSRF, authorization, filter, and OAuth layers

Patch available: sooperset/mcp-atlassian v0.22.0 (PR #1448 merged 2026-07-10)

https://github.com/sooperset/mcp-atlassian/pull/1448
GitHub advisoryMentions a patch (unverified)

SSRF redirect protection missing for basic-auth and OAuth authentication branches · Advisory · sooperset/mcp-atlassian · GitHub

https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6529-c226-h328

Vendor Advisories for CVE-2026-77261(1)

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

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
pipmcp-atlassian @ 0.22.0 (fixes < 0.22.0)—ghsa

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

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
mcp-atlassian0.1.1 ... 0.9.0 (79 versions)
  • every version up to 0.22.0: fixed in 0.22.0
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 33× 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.

  1. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  2. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  3. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  4. 2026-11-09 20:03 UTCEchelonGraph re-scored
  5. 2026-11-09 20:03 UTCGHSA enrichmentGHSA-6529-c226-h328 · GitHub severity HIGH · GitHub CVSS 7.1
  6. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  7. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  8. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  9. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  10. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  11. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  12. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  13. 2026-11-03 07:35 UTCEchelonGraph re-scored
  14. 2026-11-03 07:35 UTCGHSA enrichmentGHSA-6529-c226-h328 · GitHub severity HIGH · GitHub CVSS 7.1
  15. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  16. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  17. 2026-11-01 07:39 UTCGHSA enrichmentGHSA-6529-c226-h328 · GitHub severity HIGH · GitHub CVSS 7.1
  18. 2026-11-01 07:39 UTCEchelonGraph re-scored
  19. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  20. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  21. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  22. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  23. 2026-10-27 18:48 UTCEchelonGraph re-scored
  24. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  25. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
Show 64 more
  1. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  2. 2026-10-25 14:01 UTCEchelonGraph re-scored
  3. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  4. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  5. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  6. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  7. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  8. 2026-10-20 08:12 UTCEchelonGraph re-scored
  9. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  10. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  11. 2026-10-18 03:12 UTCEchelonGraph re-scored
  12. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  13. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  14. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  15. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  16. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  17. 2026-10-13 06:58 UTCEchelonGraph re-scored
  18. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  19. 2026-10-12 15:37 UTCEchelonGraph re-scored
  20. 2026-10-11 19:23 UTCEchelonGraph re-scored
  21. 2026-10-11 16:39 UTCEchelonGraph re-scored
  22. 2026-10-11 13:55 UTCEchelonGraph re-scored
  23. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  24. 2026-10-11 02:41 UTCEchelonGraph re-scored
  25. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  26. 2026-10-10 04:47 UTCEchelonGraph re-scored
  27. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  28. 2026-10-08 20:15 UTCEchelonGraph re-scored
  29. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  30. 2026-10-08 09:25 UTCEchelonGraph re-scored
  31. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  32. 2026-10-07 00:55 UTCEchelonGraph re-scored
  33. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  34. 2026-10-06 03:16 UTCEchelonGraph re-scored
  35. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  36. 2026-10-05 05:36 UTCEchelonGraph re-scored
  37. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  38. 2026-10-03 20:48 UTCEchelonGraph re-scored
  39. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  40. 2026-10-02 23:08 UTCEchelonGraph re-scored
  41. 2026-10-02 01:24 UTCEchelonGraph re-scored
  42. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  43. 2026-09-30 16:57 UTCEchelonGraph re-scored
  44. 2026-09-29 19:19 UTCEchelonGraph re-scored
  45. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  46. 2026-09-28 21:38 UTCEchelonGraph re-scored
  47. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  48. 2026-09-28 00:00 UTCEchelonGraph re-scored
  49. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  50. 2026-09-27 02:22 UTCEchelonGraph re-scored
  51. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  52. 2026-09-26 04:43 UTCEchelonGraph re-scored
  53. 2026-09-26 00:28 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  54. 2026-09-25 17:50 UTCEchelonGraph re-scored▲ 1.40
  55. 2026-09-25 17:49 UTCNVD updateCVSS v3 → 8.5
  56. 2026-09-24 16:05 UTCEchelonGraph re-scored
  57. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  58. 2026-09-23 18:26 UTCEchelonGraph re-scored
  59. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  60. 2026-09-23 15:20 UTCEchelonGraph re-scored
  61. 2026-09-23 14:50 UTCEchelonGraph re-scored
  62. 2026-09-22 18:30 UTCEchelonGraph re-scored
  63. 2026-09-22 18:08 UTCEchelonGraph re-scoredFirst assessed: 7.1 HIGH
  64. 2026-09-22 18:08 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-77261?
CVE-2026-77261 is a high-severity vulnerability; its CVE record was published on September 22, 2026. MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, _make_ssrf_safe_hook is omitted from JiraFetcher and ConfluenceFetcher sessions created through the basic-auth and oauth_pat branches. If an attacker-controlled or compromised…
When was the CVE record for CVE-2026-77261 published?
The CVE record for CVE-2026-77261 was published on September 22, 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 25, 2026; the record at its source may have been updated since.
Is CVE-2026-77261 actively exploited?
CVE-2026-77261 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (31st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77261?
CVE-2026-77261 has a CVSS v3 base score of 8.5 (NVD).
How do I remediate CVE-2026-77261?
A fix for CVE-2026-77261 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-77261 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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