Mastodon is a free, open-source social network server based on ActivityPub. FASP registration requires manual approval by an administrator. In versions 4.4.0 through 4.4.13 and 4.5.0 through 4.5.6, actions performed by a FASP to subscribe to account/content lifecycle events or to backfill content did not check properly whether the FASP was actually approved. This only affects Mastodon servers that have opted in to testing the experimental FASP feature by setting the environment variable EXPERIMENTAL_FEATURES to a value including fasp. An attacker can make subscriptions and request content backfill without approval by an administrator. Done once, this leads to minor information leak of URIs that are publicly available anyway. But done several times this is a serious vector for DOS, putting pressure on the sidekiq worker responsible for the fasp queue. The fix is included in the 4.4.14 and 4.5.7 releases. Admins that are actively testing the experimental "fasp" feature should update their systems. Servers not using the experimental feature flag fasp are not affected.
CVE-2026-27468
“—” beside the score: it is equal to NVD's CVSS score.
This high-severity CVE scores 8.2 under NVD CVSS v3. EPSS exploit probability: 0.3% (22nd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Also known asEUVD-2026-8546 (ENISA EUVD)Source: ENISA EUVD
- High severity, but no confirmed exploitation yet
A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).
- CVSS v3
- 8.2
- EG Score
- 8.2HIGHmedium confidence
- EG Risk
- 37EG Risk 37/100
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)Severity82% × 45%Impact severity (EG Severity): CVSS 8.2 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.3% × 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 referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule. - EPSS PROB
- 0.3%
- EPSS %ILE
- 22nd
- 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 (8.2): severity, escalated by confirmed exploitation. This CVE's 8.2 is its impact severity (EG Severity), not escalated.
- EG Severity
- 8.2 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
- 0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). 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.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.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 referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.
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.
No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.
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
February 24, 2026
Last Modified
June 17, 2026
Advisory Details (2)
Auto-updated Aug 2, 2026Allowing unconfirmed FASP to make subscriptions · Advisory · mastodon/mastodon · GitHub
https://github.com/mastodon/mastodon/security/advisories/GHSA-qgmm-vr4c-ggjgcommit 6ba6285a73c3 (mastodon/mastodon)
Fix landed in mastodon/mastodon commit 6ba6285a73c3 — awaiting tagged release
https://github.com/mastodon/mastodon/commit/6ba6285a73c3a8b281123814d45f534e3bcebb96Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 7× in last 7d / 39× 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 97 of 104 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. 3 repeat rows among the latest 100 are merged into the row they repeat. The 7 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
- 2026-10-31 18:40 UTCEG score recompute
- 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.3% · 20th percentile
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.3% · 20th percentile
- 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.3% · 20th percentile
- 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.3% · 20th percentile
- 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.3% · 20th percentile
- 2026-10-25 14:38 UTCEG score recompute
- 2026-10-24 17:21 UTCEG score recompute
- 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
- 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.5% · 40th percentile
- 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.5% · 40th percentile
- 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-10-18 03:51 UTCEG score recompute
- 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-10-17 16:26 UTCEG score recompute
- 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 36th percentile
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- 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-10-12 16:17 UTCEG score recompute
- 2026-10-11 19:59 UTCEG score recompute
- 2026-10-11 17:13 UTCEG score recompute
- 2026-10-11 14:44 UTCEG score recompute
- 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-10-09 06:55 UTCOSV refresh
- 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-19 13:33 UTCOSV refresh
- 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 17th percentile
- 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-31 17:04 UTCOSV refresh
- 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 17th percentile
- 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-14 09:05 UTCEG score recompute
- 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-13 01:05 UTCEG score recompute
- 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-12 00:51 UTCEG score recompute
- 2026-08-11 13:42 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-11 06:32 UTCEG score recompute
- 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-09 20:54 UTCEG score recompute
- 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-09 08:43 UTCEG score recompute
- 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-07 20:49 UTCEG score recompute
- 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-06 03:04 UTCEG score recompute
- 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.2% · 15th percentile
- 2026-08-04 05:57 UTCEG score recompute
- 2026-08-03 10:36 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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Frequently asked(5)
What is CVE-2026-27468?
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How do I remediate CVE-2026-27468?
Dependency Blast Radius
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