OCTOBER 10, 2026
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Case File

CVE-2026-91777

HIGH · CVSS 7.5 EPSS 0.45% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-09-23 · Last synced 2026-10-10

CyberRota Analysis

AI-Generated

The vulnerability affects the FasterXML jackson-databind library, specifically in the deserialization process of identity-enabled collections and maps, where it performs inefficient linear scans for unresolved object-ID references. This can lead to significant CPU resource consumption, resulting in denial-of-service conditions when processing maliciously crafted JSON documents. Organizations using this library for deserializing JSON data should prioritize patching to mitigate the risk of exploitation.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Detected Signals
exploit

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-91777
Severity
HIGH
CVSS
7.5
EPSS
0.45%

Original NVD Description

Forward-reference completion for @JsonIdentityInfo object IDs in FasterXML jackson-databind performs a linear scan of the pending-reference accumulator for every resolved ID. The affected paths are CollectionDeserializer.CollectionReferringAccumulator.resolveForwardReference() and the equivalent implementation in MapDeserializer. When a document first creates N unresolved object-ID references in an identity-enabled collection or map and then defines those same IDs in reverse order, completion performs on the order of N * (N + 1) / 2 identity comparisons, so a shallow document whose size grows linearly causes quadratic CPU work during deserialization. The reporter instrumented equals() calls on the ID class and measured exactly 2,003,000 comparisons at N = 2,000, against zero comparisons in the pending-reference lookup path for an equally sized control in which every reference was already resolved. The input requires no deep nesting and no syntactically unusual JSON. Exploitation requires an application that deserializes attacker-influenced JSON into an identity-enabled collection or map. The fix replaces the repeated linear lookup with a keyed pending-reference structure.