Asterisk is an open source private branch exchange and telephony toolkit. Prior to Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3, an unbounded sscanf in res_pjsip_pubsub when parsing the MWI NOTIFY Message-Account field may allow an unauthenticated attacker to send a carefully crafted packet that causes a stack buffer overflow and corrupts the underlying transport, permanently disabling all SIP functionality. An Asterisk restart is required to restore full operation. This issue is fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3.
CVE-2026-57191
This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6% (48th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Also known asEUVD-2026-111397 (ENISA EUVD)Source: ENISA EUVD
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 8.2
- EG Score
- 8.2HIGHlow 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% × 40%No KEV listing, EG-KEV tier or EPSS when EchelonGraph scored this CVE.Automatability0% × 15%CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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. - EPSS PROB
- 0.6%
- EPSS %ILE
- 48th
- 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.a secondary CVSS source · CVSS v3.0 or v3.1
- EG Likelihood
- 0.6% within 30 daysSource: FIRST EPSS. 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.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 available. Apply it within your standard update timelines.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” 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
October 27, 2026
Last Modified
October 28, 2026
Advisory Details (10)
Auto-updated Oct 27, 2026Asterisk Release 21.12.3
Patch available: asterisk/asterisk 21.12.3
https://github.com/asterisk/asterisk/releases/tag/21.12.3Asterisk Release 20.20.1
Patch available: asterisk/asterisk 20.20.1
https://github.com/asterisk/asterisk/releases/tag/20.20.1commit ee1b66a5e407 (asterisk/asterisk)
Fix landed in asterisk/asterisk commit ee1b66a5e407 — awaiting tagged release
https://github.com/asterisk/asterisk/commit/ee1b66a5e40733ba0b9fad7fc4d032cabbe1dd75commit dca516f6d895 (asterisk/asterisk)
Fix landed in asterisk/asterisk commit dca516f6d895 — awaiting tagged release
https://github.com/asterisk/asterisk/commit/dca516f6d895e8867d48fa56b6ce7f05b6f7457acommit b5281828dad7 (asterisk/asterisk)
Fix landed in asterisk/asterisk commit b5281828dad7 — awaiting tagged release
https://github.com/asterisk/asterisk/commit/b5281828dad7d44658439ba6393fe6be3328a4bdcommit b4be3bd67ce4 (asterisk/asterisk)
Fix landed in asterisk/asterisk commit b4be3bd67ce4 — awaiting tagged release
https://github.com/asterisk/asterisk/commit/b4be3bd67ce4ac35b94fbfa860cdd9e1c906610bcommit 7a1ffcdf38cc (asterisk/asterisk)
Fix landed in asterisk/asterisk commit 7a1ffcdf38cc — awaiting tagged release
https://github.com/asterisk/asterisk/commit/7a1ffcdf38cc76d1c4eae51651667f3fd4548ab0commit 647b35c3cfd4 (asterisk/asterisk)
Fix landed in asterisk/asterisk commit 647b35c3cfd4 — awaiting tagged release
https://github.com/asterisk/asterisk/commit/647b35c3cfd4a2cc3b1fb7560b085feba5c24b4bcommit 0e8951408449 (asterisk/asterisk)
Fix landed in asterisk/asterisk commit 0e8951408449 — awaiting tagged release
https://github.com/asterisk/asterisk/commit/0e89514084490070c5ecee419ec5ee37b7c49528Stack buffer overflow in MWI NOTIFY Message-Account parsing · Advisory · asterisk/asterisk · GitHub
https://github.com/asterisk/asterisk/security/advisories/GHSA-589g-qgf8-m6mxWeakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 9× 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.
- 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-27 22:28 UTCEG score recompute
- 2026-10-27 22:01 UTCENISA EUVD ID recordedEUVD-2026-111397 · Source: ENISA EUVD
- 2026-10-27 21:48 UTCEG score recomputeFirst assessed: 8.2 HIGH
- 2026-10-27 21:45 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
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