Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
The jawn-parser package (Maven org.typelevel:jawn-parser_2.12, jawn-parser_2.13 and jawn-parser_3) is affected in versions before 1.7.0. When AsyncParser receives a single large JSON token split across many small chunks, it rescans the incomplete token on each call, so parsing time grows quadratically with input length. An attacker who can send large tokens and control chunk sizes can exhaust CPU and cause denial of service. Upgrade to 1.7.0 or later; if you cannot upgrade, use the synchronous Parser or buffer input into larger chunks before calling absorb.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 7.5 | High | 3.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0075, the 55th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:16 UTC First seen by agentprime
- 31 Oct 2026, 14:16 UTC Confirmed by OSV