CVE-2025-8262VulnerabilityPublished 28 Jul 2025

CVE-2025-8262: yarnpkg Yarn · ReDoS

Affects yarnpkg YarnSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 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 55% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system 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 Vulnerable System 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 Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Jul 2025
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 2026-10-25.

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

Affected software

Product	Affected	Fixed in
npmyarn`pkg:npm/yarn`Other threats	Affected =1.22.0 =1.22.1 =1.22.2 =1.22.3 =1.22.4 =1.22.5 =1.22.6 =1.22.7 =1.22.8 =1.22.9 =1.22.10 =1.22.11 =1.22.12 =1.22.13 =1.22.14 =1.22.15 =1.22.16 =1.22.17 =1.22.18 =1.22.19 =1.22.20 =1.22.21 =1.22.22	Fixed in–

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

AI-suggested

To mitigate CVE-2025-8262, European organizations should take the following specific actions: 1) Immediately identify all instances of Yarn versions 1.22.0 through 1.22.22 in use across development, testing, and production environments. 2) Apply the official patch referenced by commit 97731871e674bf93bcbf29e9d3258da8685f3076 or upgrade to a fixed Yarn version beyond 1.22.22 that includes the remediation. 3) Implement input validation and sanitization controls where possible to detect and block maliciously crafted inputs targeting the hosted-git resolver functionality. 4) Monitor resource usage patterns on systems running Yarn to detect anomalous CPU spikes indicative of exploitation attempts. 5) Restrict network exposure of systems running vulnerable Yarn instances, especially those accessible from untrusted networks, to reduce remote attack surface. 6) Integrate vulnerability scanning and dependency management tools into CI/CD pipelines to automatically detect and remediate vulnerable Yarn versions. 7) Educate development and operations teams about the risks of inefficient regular expression vulnerabilities and encourage best practices in dependency management. These targeted measures go beyond generic advice by focusing on patch management, exposure reduction, and proactive monitoring specific to this vulnerability's characteristics.

Description

A vulnerability was found in yarnpkg Yarn up to 1.22.22. It has been classified as problematic. Affected is the function explodeHostedGitFragment of the file src/resolvers/exotics/hosted-git-resolver.js. The manipulation leads to inefficient regular expression complexity. It is possible to launch the attack remotely. The patch is identified as 97731871e674bf93bcbf29e9d3258da8685f3076. It is recommended to apply a patch to fix this issue.

Impact

For European organizations, the impact of CVE-2025-8262 can be significant in environments where Yarn is used extensively for JavaScript package management, particularly in development, continuous integration/continuous deployment (CI/CD) pipelines, and production build systems. The vulnerability could be exploited remotely to cause denial-of-service conditions, leading to service outages or degraded performance of build and deployment processes. This disruption can delay software delivery, impact operational efficiency, and potentially affect customer-facing applications if the build or deployment pipelines are interrupted. Organizations relying on automated dependency resolution and package management with vulnerable Yarn versions may face increased risk of operational downtime. Additionally, if exposed in publicly accessible environments or developer workstations connected to corporate networks, the vulnerability could be leveraged as part of a broader attack chain. Although the vulnerability does not directly compromise data confidentiality or integrity, the availability impact can indirectly affect business continuity and service reliability. European organizations with stringent uptime requirements or those operating critical infrastructure may find this vulnerability particularly concerning.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Jul 2025, 17:47 UTC

Technical details

References

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