NVD / CVE Program· CNA hackerone

CVE-2026-77164: Circles' remote-instance signature verification fetches the attacker-supplied keyId URL before trust in the remote instance is established,

Noroxi assessment

Priority: Monitor (action score 24/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.18% (FIRST EPSS).
Someone with local access to the system can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Circles' remote-instance signature verification fetches the attacker-supplied keyId URL before trust in the remote instance is established, and explicitly allows local/private addresses for this request, bypassing Nextcloud's core SSRF protections. The public, unauthenticated endpoints POST /apps/circles/event/ and POST /apps/circles/incoming/ reach this code path, allowing any unauthenticated user to force the server to issue a GET request to an internal address. The response body of the internal request is never returned to the requester, so this is blind SSRF: an attacker can determine whether an internal service is reachable, but cannot read its response contents through this endpoint alone.

MediumCVSS 6.2 · v3.0—No exploit No fix recorded

SSRF

EUVD-2026-82621

Published: Sep 17, 2026
Updated: Sep 18, 2026
EPSS: 0.1% · 8th percentile
CWE: CWE-918

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 24 / 40 · 6.2 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · hackerone: 6.2; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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Not in KEV: no record of exploitation in the wild
No public exploit code on record
No fixed version yet

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (hackerone). Independent of NVD's CPE analysis and usually ahead of it.

Nextcloud Server
- 31.0.0 and later · up to and including 32.0.0affected · semver

Same product

nextcloud: all records

Other highest-scoring records for the same primary product.

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CVE-2026-77165File owners were unable to unlock TYPE_TOKEN locks placed by other users, leaving files permanently locked with no recovery path outside of
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Published before and after this one in the same product

← EarlierCVE-2021-41179Oct 25, 2021 · Two-Factor Authentication not enforced for pages marked as public
26Monitor
← EarlierCVE-2026-68493Sep 17, 2026 · After guessing a 62^15 complex unique identifier, a malicious logged in user was able to retrieve a list of memberships for a circle they ar
12Monitor
Later →CVE-2026-82985Sep 17, 2026 · The Photos app's filter-based "smart albums" build their file listing using the search configuration (photosSourceFolders) of the user viewi
26Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Balvant Chavda (0x0doteth)finder

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope