Home/CVE/PyJWT is a JSON Web Token implementation in Python. Prior to 2.12.0, PyJWT does not validate the crit (Critical) Header
CVE
CVE-2026-32597
PyJWT is a JSON Web Token implementation in Python. Prior to 2.12.0, PyJWT does not validate the crit (Critical) Header
PyJWT is a JSON Web Token implementation in Python. Prior to 2.12.0, PyJWT does not validate the crit (Critical) Header Parameter defined in RFC 7515 §4.1.11. When a JWS token contains a crit array listing extensions that PyJWT does not understand, the library accepts the token instead of rejecting it.
This violates the MUST requirement in the RFC. This vulnerability is fixed in 2.12.0.
HIGH · CVSS 7.5
EPSS 0.00014
Act now
- Public exploit or PoC is available
- SSVC automatable: yes - attacks can be scripted at scale
- CVSS base score ≥ 7.0
Sigma rules0
YARA rules0
Look this up elsewhere - one-click external pivots
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How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2026-32597, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
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ATT&CK techniques
6Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.
T1211 · Exploitation for Stealth T1491 · Defacement T1542.002 · Component Firmware T1556 · Modify Authentication Process T1557.002 · ARP Cache Poisoning T1584.002 · DNS Server
▤ Build a SIEM detection for these techniques
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CAPEC attack patterns
12Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.
CAPEC-CAPEC-111 · JSON Hijacking (aka JavaScript Hijacking) CAPEC-CAPEC-141 · Cache Poisoning CAPEC-CAPEC-142 · DNS Cache Poisoning CAPEC-CAPEC-148 · Content Spoofing CAPEC-CAPEC-218 · Spoofing of UDDI/ebXML Messages CAPEC-CAPEC-384 · Application API Message Manipulation via Man-in-the-Middle CAPEC-CAPEC-385 · Transaction or Event Tampering via Application API Manipulation CAPEC-CAPEC-386 · Application API Navigation Remapping CAPEC-CAPEC-387 · Navigation Remapping To Propagate Malicious Content CAPEC-CAPEC-388 · Application API Button Hijacking CAPEC-CAPEC-665 · Exploitation of Thunderbolt Protection Flaws CAPEC-CAPEC-701 · Browser in the Middle (BiTM)
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Weakness Classification
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Affected Products & Versions
1pyjwt project pyjwt< 2.12.0
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Affected Packages
1Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
PyPI
pyjwt
HIGH
fixed in 2.12.0
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Public Exploits & PoCs
2These PoC and exploit links come from public sources and are not verified to be safe or functional. Review the code before running anything, and treat unverified entries as untrusted.
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Fixed versions by distribution
80The package version that resolves this CVE on each Linux distribution, from the vendor’s published security data. fixed in shows a patched version exists; open means the package is listed as affected with no fix yet.
oracle allfence-agents-aliyun open
oracle allfence-agents-all open
oracle allfence-agents-amt-ws fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-apc open
oracle allfence-agents-apc-snmp open
oracle allfence-agents-aws open
oracle allfence-agents-azure-arm open
oracle allfence-agents-bladecenter fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-brocade fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-cisco-mds open
oracle allfence-agents-cisco-ucs fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-common open
oracle allfence-agents-compute fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-drac5 fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-eaton-snmp open
oracle allfence-agents-emerson fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-eps fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-gce fixed in 0:4.16.0-13.el10_1.4
oracle allfence-agents-heuristics-ping open
oracle allfence-agents-hpblade fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-ibm-powervs open
oracle allfence-agents-ibm-vpc fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-ibmblade open
oracle allfence-agents-ifmib fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-ilo-moonshot open
oracle allfence-agents-ilo-mp fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-ilo-ssh open
oracle allfence-agents-ilo2 open
oracle allfence-agents-intelmodular fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-ipdu fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-ipmilan fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-kdump fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-kubevirt fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-lpar open
oracle allfence-agents-mpath fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-nutanix-ahv open
oracle allfence-agents-openstack open
oracle allfence-agents-redfish open
oracle allfence-agents-rhevm open
oracle allfence-agents-rsa fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-rsb fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-sbd fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-scsi fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-virsh fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-vmware-rest fixed in 0:4.2.1-129.el8_10.25
oracle allfence-agents-vmware-soap open
oracle allfence-agents-wti fixed in 0:4.2.1-129.el8_10.25
oracle allfence-virt fixed in 0:4.16.0-13.el10_1.4
oracle allfence-virtd open
oracle allfence-virtd-cpg fixed in 0:4.16.0-13.el10_1.4
oracle allfence-virtd-libvirt open
oracle allfence-virtd-multicast fixed in 0:4.16.0-13.el10_1.4
oracle allfence-virtd-serial fixed in 0:4.16.0-13.el10_1.4
oracle allfence-virtd-tcp open
oracle allha-cloud-support fixed in 0:4.16.0-13.el10_1.4
rhel 8fence-agents-aliyun open
rhel 8fence-agents-all open
rhel 8fence-agents-amt-ws fixed in 0:4.2.1-129.el8_10.25
rhel 8fence-agents-apc fixed in 0:4.2.1-129.el8_10.25
rhel 8fence-agents-apc-snmp open
rhel 8fence-agents-aws fixed in 0:4.2.1-129.el8_10.25
rhel 8fence-agents-azure-arm open
rhel 8fence-agents-bladecenter open
rhel 8fence-agents-brocade open
rhel 8fence-agents-cisco-mds fixed in 0:4.2.1-129.el8_10.25
rhel 8fence-agents-cisco-ucs open
rhel 8fence-agents-common open
rhel 8fence-agents-compute fixed in 0:4.2.1-129.el8_10.25
rhel 8fence-agents-drac5 fixed in 0:4.2.1-129.el8_10.25
rhel 8fence-agents-eaton-snmp fixed in 0:4.2.1-129.el8_10.25
rhel 8fence-agents-emerson fixed in 0:4.2.1-129.el8_10.25
rhel 8fence-agents-eps open
rhel 8fence-agents-gce open
rhel 8fence-agents-heuristics-ping open
rhel 8fence-agents-hpblade open
rhel 8fence-agents-ibm-powervs open
rhel 8fence-agents-ibm-vpc fixed in 0:4.2.1-129.el8_10.25
rhel 8fence-agents-ibmblade fixed in 0:4.2.1-129.el8_10.25
rhel 8fence-agents-ifmib open
rhel 8fence-agents-ilo-moonshot fixed in 0:4.2.1-129.el8_10.25
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Scoring & Timeline
7.5
HIGH · CVSS v3.1 · [email protected]
Attack Vector
Network
Adjacent
Local
Physical
Attack Complexity
Low
High
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
SSVC triage · cisa-vulnrichment
Exploitation
poc
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
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Vendor Advisories
30🔗
References & Sources
1Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.