A flaw in Libsoup’s server‑side digest authentication implementation fails to enforce nonce‑count progression and to track issued nonces, allowing a remote attacker to capture a single valid authentication header and replay it indefinitely. The attacker can thereby bypass authentication and impersonate a legitimate user, leading to unauthorized access, potential data tampering, and loss of confidentiality or integrity for resources protected by this mechanism.

Red Hat Enterprise Linux releases 6, 7, 8, 9, and 10 are affected, as are systems that ship the GNOME Libsoup library. No specific version numbers are listed; the flaw applies to the Libsoup packages bundled with these operating systems and the referenced component.

The CVSS score of 5.8 signals moderate severity, while an EPSS value below 1% indicates a low current probability of exploitation. The vulnerability is not listed in the CISA KEV catalog. Exploitation requires only the ability to capture a valid HTTP Digest Authorization header over the network; the attacker can then replay that header with no additional privileges or access rights. Because no patch or widely applicable workaround is presently available, the risk persists as long as Digest authentication remains in use. The likely attack vector is a remote attacker observing traffic to a service that enables Digest authentication, capturing a single valid Authorization header, and replaying it repeatedly to gain access.