CVE-2026-49852
joserfc: HS256/HS384/HS512 verify accepts empty/nil HMAC key (cross-language sibling of CVE-2026-45363)
02 Description
joserfc: HS256/HS384/HS512 verify accepts empty/nil HMAC key (cross-language sibling of CVE-2026-45363)
03 Exploitation and scoring
- Exploitation
- Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
- SSVC decision
- ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
- AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 0.17% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 6.4% of scored records. A rank, not a probability.
- NVD base score
- 8.7 (CVSS v4.0), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- NVD analysis status
- Deferred. NVD last modified this record on 2026-10-24.
- Red Hat severity
- Important. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-07-17 19:14Z3 MO AGO
- Last updated
- 2026-07-20 14:58Z3 MO AGO
- Reserved
- 2026-06-01
- Assigning CNA
- GitHub_M
- Record state
- PUBLISHED
- Severity
- High (CVSS 8.7)
- CNA CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- Weaknesses
- Data version
- 5.2
- Document digest
- 33d6c5ee015b475787bdb5e3ec5e60ec34527a6a0252aee968c4ad66067c8a84
05 Affected products
06 References
07 Fixed in
Debian 13
- joserfc No fix yet
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- joserfc Fixed in 1.6.8-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 26.04 LTS
- joserfc No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.