High [CVE-2026-54896] Heap buffer overflow in exception serialization
This high-severity Red Hat Linux advisory covers CVE-2026-54896.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
Summary
Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, when in object mode, Oj.dump is vulnerable to a heap buffer overflow when serializing Exception objects with a large:indent value.
The serializer allocates a buffer sized for the object's attributes but does not account for the indent bytes added on each write. With indent: 5000, the accumulation of 5,000-byte indent strings overflows the 13,150-byte heap allocation, corrupting adjacent heap memory.
This issue has been fixed in version 3.17.2. A flaw was found in Oj (Optimized JSON), a Ruby gem used for processing JSON data.
This vulnerability occurs when the software attempts to serialize (convert into a format for storage or transmission) Exception objects with a very large indentation setting. The internal process for handling this serialization does not properly manage memory, leading to a heap buffer overflow.
This memory corruption could allow an attacker to disrupt the application, causing a denial of service, or potentially execute unauthorized code. Red Hat's only product shipping the Oj Ruby gem (Compliance Backend) already includes version 3.17.3, which contains the fix for this vulnerability.
No Red Hat products are affected. Red Hat severity: Important — CVSS 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
Weakness: CWE-787.
Is CVE-2026-54896 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-54896 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-54896?
Upgrade to a fixed release named by Red Hat:
- 3.17.2
Confirm against the vendor advisory before you patch.
- < 3.17.2
Official advisory · high-confidence parse· fetched 11 days ago·verify at source
Mitigation
Upgrade to a fixed release: 3.17.2. That is the remediation for this advisory.
The vendor advisory may list interim mitigations or workarounds not captured here. Review it before change work.
Official advisory · high-confidence parse· fetched 11 days ago·verify at source
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