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CVE-2026-56812

Improper Check for Unusual or Exceptional Conditions vulnerability in phoenixframework phoenix (Presence JavaScript client) allows an attacker with ordinary channel access to cause a persistent client-side denial of service against every viewer of a presence channel topic. This vulnerability is associated with program files assets/js/phoenix/presence.js and program routines Presence.syncState and Presence.syncDiff. The Phoenix JavaScript presence client checks whether a presence already exists
Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:832e3246aca9eaba0e240d7db623189566b4180515da844fd4698b65b5ddcdb7
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
1

Preserved source conflicts

No provider value was silently selected as the winner.

affected · 3 assertions

{"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:phoenixframework:phoenix:*:*:*:*:*:*:*:*"],"defaultStatus":"unaffected","modules":["Presence"],"packageName":"phoenix","packageURL":"pkg:hex/phoenix","product":"phoenix","programFiles":["assets/js/phoenix/presence.js"],"programRoutines":[{"name":"Presence.syncState"},{"name":"Presence.syncDiff"}],"repo":"https://github.com/phoenixframework/phoenix","vendor":"phoenixframework","versions":[{"lessThan":"1.5.15","status":"affected","version":"1.2.0-rc.0","versionType":"semver"},{"lessThan":"1.6.17","status":"affected","version":"1.6.0-rc.0"…

  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/affected/0

{"collectionURL":"https://github.com","cpes":["cpe:2.3:a:phoenixframework:phoenix:*:*:*:*:*:*:*:*"],"defaultStatus":"unaffected","modules":["Presence"],"packageName":"phoenixframework/phoenix","packageURL":"pkg:github/phoenixframework/phoenix","product":"phoenix","programFiles":["assets/js/phoenix/presence.js"],"programRoutines":[{"name":"Presence.syncState"},{"name":"Presence.syncDiff"}],"repo":"https://github.com/phoenixframework/phoenix","vendor":"phoenixframework","versions":[{"changes":[{"at":"7f7b971c1ea0994e3fbd1c11ddb05e780bd38ad8","status":"unaffected"},{"at":"89a1c4be161e436241e12b23…

  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/affected/2

{"collectionURL":"https://registry.npmjs.org","cpes":["cpe:2.3:a:phoenixframework:phoenix:*:*:*:*:*:*:*:*"],"defaultStatus":"unaffected","modules":["Presence"],"packageName":"phoenix","packageURL":"pkg:npm/phoenix","product":"phoenix","programFiles":["assets/js/phoenix/presence.js"],"programRoutines":[{"name":"Presence.syncState"},{"name":"Presence.syncDiff"}],"repo":"https://github.com/phoenixframework/phoenix","vendor":"phoenixframework","versions":[{"lessThan":"1.5.15","status":"affected","version":"1.2.0-rc.0","versionType":"semver"},{"lessThan":"1.6.17","status":"affected","version":"1.6.…

  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/affected/1

Affected products and versions

3 source assertions
{"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:phoenixframework:phoenix:*:*:*:*:*:*:*:*"],"defaultStatus":"unaffected","modules":["Presence"],"packageName":"phoenix","packageURL":"pkg:hex/phoenix","product":"phoenix","programFiles":["assets/js/phoenix/presence.js"],"programRoutines":[{"name":"Presence.syncState"},{"name":"Presence.syncDiff"}],"repo":"https://github.com/phoenixframework/phoenix","vendor":"phoenixframework","versions":[{"lessThan":"1.5.15","status":"affected","version":"1.2.0-rc.0","versionType":"semver"},{"lessThan":"1.6.17","status":"affected","version":"1.6.0-rc.0"…
  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/affected/0
{"collectionURL":"https://github.com","cpes":["cpe:2.3:a:phoenixframework:phoenix:*:*:*:*:*:*:*:*"],"defaultStatus":"unaffected","modules":["Presence"],"packageName":"phoenixframework/phoenix","packageURL":"pkg:github/phoenixframework/phoenix","product":"phoenix","programFiles":["assets/js/phoenix/presence.js"],"programRoutines":[{"name":"Presence.syncState"},{"name":"Presence.syncDiff"}],"repo":"https://github.com/phoenixframework/phoenix","vendor":"phoenixframework","versions":[{"changes":[{"at":"7f7b971c1ea0994e3fbd1c11ddb05e780bd38ad8","status":"unaffected"},{"at":"89a1c4be161e436241e12b23…
  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/affected/2
{"collectionURL":"https://registry.npmjs.org","cpes":["cpe:2.3:a:phoenixframework:phoenix:*:*:*:*:*:*:*:*"],"defaultStatus":"unaffected","modules":["Presence"],"packageName":"phoenix","packageURL":"pkg:npm/phoenix","product":"phoenix","programFiles":["assets/js/phoenix/presence.js"],"programRoutines":[{"name":"Presence.syncState"},{"name":"Presence.syncDiff"}],"repo":"https://github.com/phoenixframework/phoenix","vendor":"phoenixframework","versions":[{"lessThan":"1.5.15","status":"affected","version":"1.2.0-rc.0","versionType":"semver"},{"lessThan":"1.6.17","status":"affected","version":"1.6.…
  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/affected/1

Provider-owned CVSS observations

1 source assertion
{"metric":{"attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":6.3,"baseSeverity":"MEDIUM","privilegesRequired":"NONE","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"LOW","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE"},"metric_type":"cvssV4_0"}
  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/metrics/0/cvssV4_0

CWE assertions

1 source assertion
{"cweId":"CWE-754","description":"CWE-754 Improper Check for Unusual or Exceptional Conditions","lang":"en","type":"CWE"}
  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/problemTypes/0/descriptions/0

Source references

8 source assertions
{"tags":["related"],"url":"https://cna.erlef.org/cves/CVE-2026-56812.html"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/references/1
{"tags":["patch"],"url":"https://github.com/phoenixframework/phoenix/commit/7f7b971c1ea0994e3fbd1c11ddb05e780bd38ad8"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/references/3
{"tags":["patch"],"url":"https://github.com/phoenixframework/phoenix/commit/89a1c4be161e436241e12b2378a719904b9bd96f"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/references/4
{"tags":["patch"],"url":"https://github.com/phoenixframework/phoenix/commit/b90b22521465ece00eb5a19d5aa2b9465b209c85"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/references/5
{"tags":["patch"],"url":"https://github.com/phoenixframework/phoenix/commit/beffc4da1e787e572121f68902c63daf4fe7d9c2"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/references/6
{"tags":["exploit"],"url":"https://github.com/phoenixframework/phoenix/security/advisories/GHSA-63mc-hw7g-86rr"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/adp/0/references/0
{"tags":["vendor-advisory","related"],"url":"https://github.com/phoenixframework/phoenix/security/advisories/GHSA-63mc-hw7g-86rr"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/references/0
{"tags":["related"],"url":"https://osv.dev/vulnerability/EEF-CVE-2026-56812"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:c9df0a5f3da7ce7698993763b4ff545fed3c96fa8f90db7fe5e561c34062fa6e · sha256:2fda77769d4e420b… · /containers/cna/references/2

Attribution and limitations

  • CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →

Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.

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