CVE-2023-49290VulnerabilityPublished 4 Dec 2023Updated 29 May 2025

CVE-2023-49290: lestrrat-go jwx · Uncontrolled Resource Consumption

Affects lestrrat-go jwxSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.2.27 when convenient.

Data as of 26 Oct 2026, 08:30 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.2.27

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Dec 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade github.com/lestrrat-go/jwx to 1.2.27.

Affected software

Product	Affected	Fixed in
Gogithub.com/lestrrat-go/jwx`pkg:golang/github.com/lestrrat-go/jwx`Other threats	Affected <1.2.27	Fixed in 1.2.27

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

The primary and only effective mitigation is to upgrade lestrrat-go/jwx to version 1.2.27 or later, or 2.0.18 or later, depending on the version line in use. Organizations should audit their codebases and dependencies to identify usage of lestrrat-go/jwx and confirm the version deployed. Additionally, implement input validation to restrict or sanitize the 'p2c' parameter in incoming JWE tokens if feasible, rejecting tokens with suspiciously high iteration counts. Monitoring CPU usage and implementing rate limiting or throttling on endpoints that process JWE tokens can help detect and mitigate potential DoS attempts. Employing Web Application Firewalls (WAFs) with custom rules to detect anomalous JWE payloads may provide additional protection. Finally, maintain an inventory of cryptographic libraries and ensure timely patching of dependencies to reduce exposure to similar vulnerabilities.

Description

lestrrat-go/jwx is a Go module implementing various JWx (JWA/JWE/JWK/JWS/JWT, otherwise known as JOSE) technologies. A p2c parameter set too high in JWE's algorithm PBES2-* could lead to a denial of service. The JWE key management algorithms based on PBKDF2 require a JOSE Header Parameter called p2c (PBES2 Count). This parameter dictates the number of PBKDF2 iterations needed to derive a CEK wrapping key. Its primary purpose is to intentionally slow down the key derivation function, making password brute-force and dictionary attacks more resource- intensive. Therefore, if an attacker sets the p2c parameter in JWE to a very large number, it can cause a lot of computational consumption, resulting in a denial of service. This vulnerability has been addressed in commit `64f2a229b` which has been included in release version 1.2.27 and 2.0.18. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Impact

For European organizations, this vulnerability poses a risk primarily to the availability of services that rely on the lestrrat-go/jwx library for JOSE-based encryption and key management, particularly those using PBES2 algorithms with PBKDF2 iteration counts controlled by untrusted inputs. An attacker could craft malicious JWE tokens with extremely high 'p2c' values, causing excessive CPU consumption and potentially leading to service outages or degraded performance. This can disrupt authentication, authorization, or secure communication workflows that depend on JWE, impacting business continuity and user experience. While the vulnerability does not compromise data confidentiality or integrity directly, denial of service can have cascading effects, especially in critical infrastructure, financial services, or healthcare sectors prevalent in Europe. Additionally, automated systems or APIs processing JWE tokens without proper input validation are at higher risk. The absence of known exploits reduces immediate threat but does not eliminate the risk, especially as attackers may develop exploits once the vulnerability becomes widely known.

Summary

CVE-2023-49290 is a medium-severity vulnerability classified under CWE-400 (Uncontrolled Resource Consumption) affecting the lestrrat-go/jwx Go module, which implements JOSE (JSON Object Signing and Encryption) standards including JWA, JWE, JWK, JWS, and JWT. The vulnerability arises from the handling of the 'p2c' parameter in the PBES2-* key management algorithms used in JWE encryption. The 'p2c' parameter specifies the number of iterations for the PBKDF2 (Password-Based Key Derivation Function 2), which is designed to slow down brute-force attacks by increasing computational cost. However, if an attacker sets this parameter to an excessively high value, it can cause the system to consume excessive CPU resources during key derivation, leading to a denial of service (DoS) condition. This vulnerability affects lestrrat-go/jwx versions prior to 1.2.27 and versions from 2.0.0 up to but not including 2.0.18. The issue has been fixed in versions 1.2.27 and 2.0.18 by limiting or properly handling the 'p2c' parameter to prevent resource exhaustion. No known exploits are currently in the wild, and no workarounds exist other than upgrading to the patched versions. The CVSS v3.1 score is 5.3 (medium), reflecting a network attack vector, no required privileges or user interaction, and impact limited to availability (denial of service). Confidentiality and integrity are not affected.

CWE-400Uncontrolled Resource Consumption (opens in a new tab)
Class weaknessLikelihood of exploit: High
The product does not properly control the allocation and maintenance of a limited resource.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place.
Architecture and Design
Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or; uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed.
Architecture and Design
Ensure that protocols have specific limits of scale placed on them.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Regular Expression Exponential Blowup (opens in a new tab)
Sustained Client Engagement (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 8 Jul 2025, 03:12 UTC

WeaknessesCWE-400

Technical details

References

Community reviews

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