CVE catalog
CVE-2026-39373
JWCrypto implements JWK, JWS, and JWE specifications using python-cryptography. Prior to 1.5.7, an unauthenticated attacker can exhaust server memory by sending crafted JWE tokens with ZIP compression
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.29% · Oct 25, 2026
JWCrypto implements JWK, JWS, and JWE specifications using python-cryptography. Prior to 1.5.7, an unauthenticated attacker can exhaust server memory by sending crafted JWE tokens with ZIP compression. The existing patch for CVE-2024-28102 limits input token size to 250KB but does not validate the decompressed output size. An unauthenticated attacker can cause memory exhaustion on memory-constrained systems. A token under the 250KB input limit can decompress to approximately 100MB. This vulnerability is fixed in 1.5.7.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | python-jwcrypto | sid | 1.5.6-1.2 | fixed |
| Debian | python-jwcrypto | forky | 1.5.6-1.2 | fixed |
| Debian | python-jwcrypto | trixie | 1.5.6-1.1~deb13u1 | fixed |
| Debian | python-jwcrypto | bookworm | 1.1.0-1+deb12u1 | vulnerable |
| Cpe | python-jwcrypto | Not reported | Not reported | vulnerable |
| Cpe | jwcrypto | Not reported | 1.5.7 | fixed |
| Opensuse | python-jwcrypto | tumbleweed | 1.5.7-2.1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | python-jwcrypto | source | sid | 1.5.6-1.1 | not yet assigned | Not reported | [1133006] |
| Debian | python-jwcrypto | source | forky | 1.5.6-1.1 | not yet assigned | Not reported | [1133006] |
| Debian | python-jwcrypto | source | trixie | 1.5.6-1.1~deb13u1 | not yet assigned | Not reported | [1133006] |
| Debian | python-jwcrypto | source | bookworm | (unfixed) | not yet assigned | Not reported | [1133006] |
| Cpe | jwcrypto | cpe | Not reported | 1.5.7 | Not reported | Not reported | Not reported |
| Opensuse | python-jwcrypto | rpm | tumbleweed | 1.5.7-2.1 | Not reported | OPENSUSE-SU-2026:10576-1 | Not reported |
Notes
[bookworm] python-jwcrypto: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [python3-jwcrypto]Affected
Source package: [python-jwcrypto]
Details (2)
1.1.0-1+deb12u1· all · bookwormAffected
nvd · python-jwcrypto · debian · bookworm; nvd · python-jwcrypto · debian · 12
1.1.0-1+deb12u1· all · bookwormAffected
nvd · python-jwcrypto · debian · bookworm; nvd · python-jwcrypto · debian · 12
[openSUSE Tumbleweed]
- [python313-jwcrypto]Unknown
Source package: [python-jwcrypto]
Details (1)
1.5.8-1.3· noarch · tumbleweedUnknown · Fixed:
1.5.7-2.1Version impact unknown
nvd · python-jwcrypto · opensuse · tumbleweed
- [python314-jwcrypto]Unknown
Source package: [python-jwcrypto]
Details (1)
1.5.8-1.3· noarch · tumbleweedUnknown · Fixed:
1.5.7-2.1Version impact unknown
nvd · python-jwcrypto · opensuse · tumbleweed
[Debian 13 (Trixie)]
- [python3-jwcrypto]Fixed
Source package: [python-jwcrypto]
Details (2)
1.5.6-1.1~deb13u1· all · trixieFixed · Fixed:
1.5.6-1.1~deb13u1nvd · python-jwcrypto · debian · 13
1.5.6-1.1~deb13u1· all · trixieFixed · Fixed:
1.5.6-1.1~deb13u1nvd · python-jwcrypto · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_10576-1.json]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-39373]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-39373]
- [https://osv.dev/vulnerability/openSUSE-SU-2026:10576-1]
- [https://security-tracker.debian.org/tracker/CVE-2026-39373]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39373.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-1610.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]