CVE-2026-81099

MEDIUMPre-NVD 6.86.8
EchelonGraph scoreMEDIUM confidence

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

Score 6.8 from GitHub Security Advisory (severity: HIGH) published 2026-08-27. A secondary CVSS source baseline 6.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week

Also known asEUVD-2026-67027 (ENISA EUVD) · GHSA-p943-9hp2-h27q (GitHub Security Advisories)Source: ENISA EUVD

6.8EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.8Exploit: None knownExposed services: Not assessed

An upstream fix is merged but not yet released — mitigate (WAF / firewall / segmentation) until the release ships, then apply it.

tiger-slack started its MCP HTTP transport without enabling the host allow-list the underlying SDK provides. mcp/src/httpServer.ts called the shared httpServerFactory helper and never set the DNS-rebinding-protection option, so the transport accepted a request whatever host it named, and a page in a browser could point a name it controlled at the address the server was bound to and drive the locally reachable Slack MCP server through the visitor's browser. The fix passes the option explicitly alongside a dependency update; the update alone would not have closed it. The repository publishes no release that brackets the fix, so the affected boundary is the commit preceding it.

CVSS v3
6.8
EG Score
6.8MEDIUMmedium confidence
EG Risk
31
EG Risk 31/100

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)
Severity68% × 45%
Impact severity (EG Severity): CVSS 6.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 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 low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (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: An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines until it ships, then apply the release.
EPSS PROB
0.2%
EPSS %ILE
11th
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 (6.8): severity, escalated by confirmed exploitation. This CVE's 6.8 is its impact severity (EG Severity), not escalated.

EG Severity
6.8 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). 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; Track* at high (mission-essential systems).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: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines until it ships, then apply the release.

Exploitation none (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.

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

August 27, 2026

Last Modified

September 23, 2026

Advisory Details (3)

Auto-updated Aug 27, 2026
Upstream fix merged — awaiting tagged release. Sources: github_pr.
Web page

Timescale tiger-slack DNS Rebinding via Disabled Host Header Allow-List | Advisories | VulnCheck

https://www.vulncheck.com/advisories/timescale-tiger-slack-dns-rebinding-via-disabled-host-header-allow-list
GitHub pull request

Enable DNS rebinding protection for dev + update deps

Fix merged in timescale/tiger-slack PR #146 on 2026-06-26 — awaiting tagged release

https://github.com/timescale/tiger-slack/pull/146
Web page

GitHub - timescale/tiger-slack: Real-time Slack ingest and MCP server to power your agentic Slack bots · GitHub

https://github.com/timescale/tiger-slack

Vendor Advisories for CVE-2026-81099(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 62× 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 99 of 151 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. 1 repeat row among the latest 100 is merged into the row it repeats. The 52 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  2. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  3. 2026-10-25 13:58 UTCEG score recompute
  4. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  5. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  6. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  7. 2026-10-22 13:53 UTCEG score recompute
  8. 2026-10-22 13:53 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  9. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  10. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  11. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  12. 2026-10-18 03:09 UTCEG score recompute
  13. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  14. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  15. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  16. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  17. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  18. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  19. 2026-10-12 14:57 UTCEG score recompute
  20. 2026-10-11 19:20 UTCEG score recompute
  21. 2026-10-11 16:37 UTCEG score recompute
  22. 2026-10-11 13:55 UTCEG score recompute
  23. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  24. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  25. 2026-10-10 09:47 UTCEG score recompute
Show 74 more
  1. 2026-10-10 09:47 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  2. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  3. 2026-10-09 07:16 UTCEG score recompute
  4. 2026-10-09 07:16 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  5. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  6. 2026-10-08 06:59 UTCEG score recompute
  7. 2026-10-08 06:59 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  8. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  9. 2026-10-07 07:16 UTCEG score recompute
  10. 2026-10-07 07:16 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  11. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  12. 2026-10-06 07:33 UTCEG score recompute
  13. 2026-10-06 07:33 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  14. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  15. 2026-10-05 05:30 UTCEG score recompute
  16. 2026-10-05 05:30 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  17. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  18. 2026-10-04 05:46 UTCEG score recompute
  19. 2026-10-04 05:46 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  20. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  21. 2026-10-03 06:03 UTCEG score recompute
  22. 2026-10-03 06:03 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  23. 2026-10-02 17:57 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  24. 2026-10-02 06:19 UTCEG score recompute
  25. 2026-10-02 06:19 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  26. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  27. 2026-10-01 05:31 UTCEG score recompute
  28. 2026-10-01 05:31 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  29. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  30. 2026-09-30 05:03 UTCEG score recompute
  31. 2026-09-30 05:03 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  32. 2026-09-28 21:16 UTCEG score recompute
  33. 2026-09-28 21:16 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  34. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  35. 2026-09-27 18:30 UTCEG score recompute
  36. 2026-09-27 18:30 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  37. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  38. 2026-09-26 18:45 UTCEG score recompute
  39. 2026-09-26 18:45 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  40. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  41. 2026-09-25 16:52 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  42. 2026-09-24 17:09 UTCEG score recompute
  43. 2026-09-24 17:09 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  44. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  45. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  46. 2026-09-23 17:25 UTCEG score recompute
  47. 2026-09-23 17:25 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  48. 2026-09-23 08:59 UTCEG score recompute
  49. 2026-09-23 08:59 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  50. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  51. 2026-09-22 09:16 UTCEG score recompute
  52. 2026-09-22 09:16 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  53. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  54. 2026-09-21 09:30 UTCEG score recompute
  55. 2026-09-21 09:30 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  56. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  57. 2026-09-20 09:46 UTCEG score recompute
  58. 2026-09-20 09:46 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  59. 2026-09-19 10:02 UTCEG score recompute
  60. 2026-09-19 10:02 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  61. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  62. 2026-09-18 10:19 UTCEG score recompute
  63. 2026-09-18 10:19 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  64. 2026-09-17 10:36 UTCEG score recompute
  65. 2026-09-17 10:36 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  66. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  67. 2026-09-16 10:51 UTCEG score recompute
  68. 2026-09-16 10:51 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  69. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  70. 2026-09-15 11:07 UTCEG score recompute
  71. 2026-09-15 11:07 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8
  72. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  73. 2026-09-14 11:01 UTCEG score recompute
  74. 2026-09-14 11:01 UTCGHSA enrichmentGHSA-p943-9hp2-h27q · GitHub severity HIGH · GitHub CVSS 6.8

Frequently asked(5)

What is CVE-2026-81099?
CVE-2026-81099 is a medium-severity vulnerability; its CVE record was published on August 27, 2026. tiger-slack started its MCP HTTP transport without enabling the host allow-list the underlying SDK provides. mcp/src/httpServer.ts called the shared httpServerFactory helper and never set the DNS-rebinding-protection option, so the transport accepted a request whatever host it named, and a page in…
When was CVE-2026-81099 made public?
CVE-2026-81099 was made public on August 26, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on August 27, 2026. EchelonGraph's copy of the record carries a last-modified date of September 23, 2026; the record at its source may have been updated since.
Is CVE-2026-81099 actively exploited?
CVE-2026-81099 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (11th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-81099?
CVE-2026-81099 has a CVSS base score of 6.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-81099?
An upstream fix for CVE-2026-81099 has been merged but is not yet in a tagged release. Until it ships, restrict network exposure of the affected system or apply the vendor's mitigation, then update to the release that contains the fix. The vendor advisories EchelonGraph has for CVE-2026-81099 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-81099

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