Seerr is an open-source media request and discovery manager for Jellyfin, Plex, and Emby. Starting in version 2.0.0 and prior to version 3.1.0, an authentication guard logic flaw in POST /api/v1/auth/jellyfin allows an unauthenticated attacker to register a new Seerr account on any Plex-configured instance by authenticating with an attacker-controlled Jellyfin server. The attacker receives an authenticated session and can immediately use the application with default permissions, including the ability to submit media requests to Radarr/Sonarr. Any Seerr deployment where all three of the following are true may be vulnerable: settings.main.mediaServerType is set to PLEX (the most common deployment).; settings.jellyfin.ip is set to "" (default, meaning Jellyfin was never configured); and settings.main.newPlexLogin is set to true (default). Jellyfin-configured and Emby-configured deployments are not affected. Version 3.1.0 of Seerr fixes this issue.
CVE-2026-27707
“—” beside the score: it is equal to NVD's CVSS score.
This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 0.6% (46th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Also known asEUVD-2026-9052 (ENISA EUVD)Source: ENISA EUVD
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 9.8
- EG Score
- 9.8CRITICALmedium confidence
- EG Risk
- 59EG Risk 59/100
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)Severity98% × 45%Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.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
- 46th
- 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 (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
- EG Likelihood
- 0.6% 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 or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days 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 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.
The score's inputs: 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
February 27, 2026
Last Modified
June 17, 2026
Advisory Details (3)
Auto-updated Oct 31, 2026Unauthenticated account registration on Plex-configured Seerr instances via Jellyfin authentication endpoint · Advisory · seerr-team/seerr · GitHub
https://github.com/seerr-team/seerr/security/advisories/GHSA-rc4w-7m3r-c2f7Release v3.1.0
Patch available: seerr-team/seerr v3.1.0
https://github.com/seerr-team/seerr/releases/tag/v3.1.0commit 4ae20684092b (seerr-team/seerr)
Patch available: seerr-team/seerr v3.1.0 (contains commit 4ae20684092b)
https://github.com/seerr-team/seerr/commit/4ae20684092b5b28527b23dfbc1a3417858fee8eWeakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 14× in last 7d / 57× 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 96 of 122 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. 4 repeat rows among the latest 100 are merged into the row they repeat. The 26 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-02 12:22 UTCEG score recompute
- 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-11-01 12:21 UTCEG score recompute
- 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-31 12:20 UTCEG score recompute
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-30 12:19 UTCEG score recompute
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-29 12:18 UTCEG score recompute
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-28 12:09 UTCEG score recompute
- 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-27 12:08 UTCEG score recompute
- 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-26 12:05 UTCEG score recompute
- 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-25 14:38 UTCEG score recompute
- 2026-10-25 12:01 UTCEG score recompute
- 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-24 11:58 UTCEG score recompute
- 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-23 11:56 UTCEG score recompute
- 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-22 11:54 UTCEG score recompute
- 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
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- 2026-10-21 11:52 UTCEG score recompute
- 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-20 11:51 UTCEG score recompute
- 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-19 11:47 UTCEG score recompute
- 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-18 03:51 UTCEG score recompute
- 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-17 07:50 UTCEG score recompute
- 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
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- 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-15 06:47 UTCEG score recompute
- 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-14 02:30 UTCEG score recompute
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-12 22:45 UTCEG score recompute
- 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-12 16:17 UTCEG score recompute
- 2026-10-11 19:59 UTCEG score recompute
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- 2026-10-11 14:44 UTCEG score recompute
- 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-09 14:25 UTCOSV refresh
- 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-19 21:33 UTCOSV refresh
- 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.5% · 41st percentile
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- 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-09-01 01:04 UTCOSV refresh
- 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.5% · 40th percentile
- 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.5% · 40th percentile
- 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.5% · 40th percentile
- 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.5% · 40th percentile
- 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.5% · 40th percentile
- 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.5% · 40th percentile
- 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.5% · 40th percentile
- 2026-08-14 08:49 UTCEG score recompute
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Frequently asked(5)
What is CVE-2026-27707?
When was the CVE record for CVE-2026-27707 published?
Is CVE-2026-27707 actively exploited?
What is the CVSS score of CVE-2026-27707?
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Dependency Blast Radius
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