CVE-2026-16615
A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically
CVSS
6.8
Medium
EPSS
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KEV
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Exploit Today
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0-100
Published: Jul 22, 2026 · Last modified: Jul 22, 2026 · CWE-338
Not enough EPSS history yet.
A flaw was found in librest. The PKCE implementation for OAuth authorization uses the GRand function from the GLib API, a cryptographically insecure pseudo-random number generator. Because the generated "code verifier" lacks sufficient cryptographic entropy, a malicious actor can reverse-engineer the pseudo-random number generator (PRNG) seed to predict or reconstruct the code verifier string, allowing an attacker to bypass PKCE protections and successfully impersonate the client during the OAuth 2.0 authorization flow.
CVECVSSEPSSKEVRExploitTitleMod.
CVE-2026-8169—19.9%
——6ExtremeXOS (EXOS) uses a challenge-response mechanism to authorize access to the privileged debug-mode function. The challenge value is generated using an insufficiently random source, which under certain conditions may allow an attacker to predict the expected response and activate debug-mode without authorization. Depending on device configuration and version, this may enable escalation to root-level access and persistent modification of the device software stack. Exploitation requires either a valid low-privilege account on the device (remote scenario) or physical serial console access (local scenario). This vulnerability is distinct from CVE-2017-14329, which addressed a different issue involving Python script privileges.
Extreme would like to thank Hadrien Barral (Université Gustave Eiffel) and Georges-Axel Jaloyan (French Ministry of the Interior) for responsible disclosure of their findings.1dCVE-2026-135778.2 HIG17.4%
——5Dancer2 versions through 2.1.0 for Perl generate insecure session ids when required CSPRNG modules are unavailable.
Dancer2::Core::Role::SessionFactory::generate_id silently falls back to a built-in rand-derived session id unless both Math::Random::ISAAC::XS and Crypt::URandom are available.
The fallback session id is generated from a SHA-1 hash of a call to the built-in rand function, the absolute path of the Dancer2::Core::Role::SessionFactory module, an internal counter, the process id, the module instance memory address, and a shuffled string of characters (using the List::Util::shuffle function, which also uses the built-in rand function).
These are all low-entropy and easily guessed sources.
The built-in rand() function is seeded with 32-bits and considered unsuitable for security applications.
Predictable session ids could allow an attacker to gain access to systems.9hCVE-2026-162359.8 CRI22.8%
——7Crypt::Password versions through 0.28 for Perl generate insecure random values for salts.
These versions use the built-in rand function, which is predictable and unsuitable for cryptography.2dCVE-2026-93238.1 HIG34.2%
——10The urwid web display backend (urwid/display/web.py) generates web session identifiers (urwid_id) in Screen.start() by concatenating two random.randrange(10**9) calls that use Python's Mersenne Twister PRNG, which is not cryptographically secure. Each call consumes approximately 30 bits of PRNG state, and the Mersenne Twister internal state is approximately 19,937 bits, so an attacker who observes approximately 334 session IDs (for example via the X-Urwid-ID HTTP response header) can fully reconstruct the internal state and predict all past and future session IDs (Path B). The same identifier is also used as the filename of a FIFO created in the world-listable /tmp directory (for example /tmp/urwid375487765176907690.in), so any local user on the host can list /tmp to enumerate active session tokens directly (Path A). With a valid session ID, an attacker can read the victim's terminal screen via the polling endpoint, inject keystrokes into the victim's session (yielding OS-level code execution with the session owner's privileges if the session runs a shell), and inject exit sequences or flood the FIFO to terminate or crash the session. A prior Bandit S311 warning on this usage was suppressed with # noqa: S311 rather than fixed2dCVE-2026-130825.3 MED12.1%
——4GD::SecurityImage versions through 1.75 for Perl use rand to generate secrets.
The random method creates the challenge text used for the CAPTCHA by sampling characters from an array using Perl's built-in rand function, and generates a (by default) six-character string.
The built-in rand function is unsuitable for security applications because it is predictable and reversible.5dCVE-2026-630899.3 CRI14.9%
——4WireGuard Easy through 15.3.0, fixed in commit 66b292b, contains a cryptographically weak one-time link token generation vulnerability that allows unauthenticated network attackers to recover WireGuard peer credentials by brute-forcing a keyspace of at most 1000 candidate tokens per client ID, as the token is computed using CRC32 over a random value constrained to 0-999. Attackers can enumerate candidate tokens against the unauthenticated /cnf/:oneTimeLink route, which lacks rate limiting and does not validate token expiration, to obtain a peer's PrivateKey and PresharedKey and impersonate that peer on the VPN network.5d