CVE-2026-44699PoC

LOWCVSS 9.1 · CRITICAL

Exploit discussion active in current signal (1 latest mentions)

Immediate actions

Hunt for exploitation attempts and persistence artifacts
Increase monitoring for publicly documented tradecraft
Track advisory updates for patch or workaround availability

Recommended action window: High priority (within 72h)

NVD description

LibJWT is a C JSON Web Token Library. From 3.0.0 to 3.3.2, libjwt accepts an RSA JWK that does not contain an alg parameter as the verification key for an HS256/HS384/HS512 token. In the OpenSSL backend, this causes HMAC verification to run with a zero-length key, so an attacker can forge a valid JWT without knowing any secret or RSA private key. This is an algorithm-confusion authentication bypass. It affects applications that load RSA keys from JWKS where alg is omitted, which is valid JWK syntax and common in real deployments, and then choose the verification algorithm from the JWT header, for example in a kid lookup callback. This vulnerability is fixed in 3.3.3.

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1.5/ 10 priority

Sources & remediation

Other references

Weakness type (CWE)

CWE-327CWE-347

Priority

LOW

Exploitation

NONE

PoC

YES

Patch

NONE

Momentum

NONE

Threat summary

Public PoC is present in monitored signal
1 mentions across 1 observed day

What's happening

PoC mentioned or linked in 1 signal
Technical details provided in 1 signal
1 total mentions across 1 day

Deep dive

Activity timeline1 mentions / 1d

Signal classification1 categories

PoC

1100.0%

Referenced assets1 URL

By indicator

https://app.cveplayground.com/challenges/CVE-2026-44699?utm_source=x

Full discourse1 post

CVE Playground@cveplayground144d
PoC
New Challenge Lab: CVE-2026-44699 — libjwt Algorithm Confusion Exploit a vulnerable JWT verification flow in libjwt v3.3.2 to forge admin tokens using a public RSA verification key exposed via JWKS. 🏆 Medium ⚡ 200 XP 🩸 First Blood Open https://app.cveplayground.com/challenges/CVE-2026-44699?utm_source=x https://t.co/AndqTDKECh
Post summary
A challenge lab is announced for CVE-2026-44699 in libjwt, identifying an algorithm‑confusion flaw that lets attackers forge admin JWTs using an exposed public RSA key via JWKS; a PoC playground link is provided.
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