What’s Vulnerable › Vulnerabilities

CVE-2026-59990: Jawn: Uncontrolled nesting depth in JSON parser

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-23 · updated 2026-09-30
• Weakness: CWE-770

Description

Jawn is an open source JSON parser. Prior to 1.7.0, Jawn parse methods accept arbitrarily deep JSON array and object nesting without a depth limit, allowing a remote attacker who can submit untrusted JSON to grow parser contexts until the JVM heap is exhausted. The resulting java.lang.OutOfMemoryError is a fatal Scala error that is not ordinarily handled by scala.util.Try or cats.effect.IO, causing denial of service. This issue is fixed in version 1.7.0.

Affected products

• typelevel jawn: before 1.7.0

References

• https://github.com/typelevel/jawn/commit/191cb3a44e77f1afab439ee636bf66bdf3c54a04
• https://github.com/typelevel/jawn/commit/6219666641f9408498f85868f835e17bd8a72fed
• https://github.com/typelevel/jawn/commit/93ac93e9c992c11b4c03d5455d8551f9fb24da1b
• https://github.com/typelevel/jawn/commit/f6ace7e0db715de1a8c4618bed9378333a5c2214
• https://github.com/typelevel/jawn/releases/tag/v1.7.0
• https://github.com/typelevel/jawn/security/advisories/GHSA-cc4v-rvgp-2pf3

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