Summary
rPGP Potential Resource Exhaustion when handling Untrusted Messages
During a security audit, Radically Open Security discovered two vulnerabilities which allow attackers to trigger resource exhaustion vulnerabilities in rpgp by providing crafted messages. This affects general message parsing and decryption with symmetric keys.
Versions and Patches
The impact details on the message parsing component varies with different versions. We've confirmed some of the problematic behavior on older versions such as v0.10.0 and see all recent versions as affected in some form.
The affected Argon2 functionality was introduced with v0.12.0-alpha.1, earlier versions are not vulnerable.
The vulnerabilities have been fixed with version 0.14.2. We recommend all users to upgrade to this version.
References
The security audit was made possible by the NLnet Foundation NGI Zero Core grant program for rpgp.
Impact
Affected rpgp versions do not correctly set upper limits on the total reserved amount of memory when parsing long sequences of partial OpenPGP packets, which can grow to to several GiB in size. Additionally, up to 4GiB of memory is reserved for OpenPGP packets of fixed size with large length fields, even if less data is received.
Depending on existing message size restrictions and available system resources, this can cause out-of-memory conditions and crash the rpgp process or cause other system instability through memory resource exhaustion when parsing crafted messages.
Affected rpgp versions are susceptible to excessive memory allocation with values of up to 2TiB or long processing times for some decryption operations which involve the Argon2 function. An attacker can provide a valid Symmetric Key Encrypted Session Key packet (SKESK) which uses Argon2 for String-to-Key hashing with parameters that are excessive, but within specification limits of the RFC9580 OpenPGP standard. Since rpgp did not further restrict the Argon2 parameters, this can cause out-of-memory conditions and crash the rpgp process. Under some conditions, the memory resource exhaustion may trigger other system instability. Alternatively, this can make the program unresponsive via long computations. The attacker needs to trick a victim into attempting decryption, but does not require knowledge of the symmetric secret used by the victim.
There is no impact to confidentiality or integrity security properties.
The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.
CVE-2024-53857 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.14.2); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2024-53857? CVE-2024-53857 is a high-severity allocation of resources without limits or throttling vulnerability in pgp (rust), affecting versions < 0.14.2. It is fixed in 0.14.2. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
- How severe is CVE-2024-53857? CVE-2024-53857 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of pgp are affected by CVE-2024-53857? pgp (rust) versions < 0.14.2 is affected.
- Is there a fix for CVE-2024-53857? Yes. CVE-2024-53857 is fixed in 0.14.2. Upgrade to this version or later.
- Is CVE-2024-53857 exploitable, and should I be worried? Whether CVE-2024-53857 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2024-53857 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2024-53857? Upgrade
pgpto 0.14.2 or later.