Description
snac2 before 2.93 contains a heap-based buffer overflow vulnerability in _xs_json_load_lexer() that allows unauthenticated remote attackers to corrupt heap memory by sending JSON strings containing a \u0000 escape. Attackers can send a single crafted application/activity+json POST to activitypub_post_handler(), which parses it before signature checks, overflowing heap allocations and crashing the server.
Published: 2026-10-18
Score: 8.7 High
EPSS: < 1% Very Low
KEV: No
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Mon, 19 Oct 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 19 Oct 2026 13:15:00 +0000

Type Values Removed Values Added
First Time appeared Grunfink
Grunfink snac2
Vendors & Products Grunfink
Grunfink snac2

Sun, 18 Oct 2026 11:45:00 +0000

Type Values Removed Values Added
Description snac2 before 2.93 contains a heap-based buffer overflow vulnerability in _xs_json_load_lexer() that allows unauthenticated remote attackers to corrupt heap memory by sending JSON strings containing a \u0000 escape. Attackers can send a single crafted application/activity+json POST to activitypub_post_handler(), which parses it before signature checks, overflowing heap allocations and crashing the server.
Title snac2 before 2.93 Heap-Based Buffer Overflow via JSON Parser _xs_json_load_lexer()
Weaknesses CWE-122
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-19T16:05:15.544Z

Reserved: 2026-10-18T01:24:56.329Z

Link: CVE-2026-112021

cve-icon Vulnrichment

Updated: 2026-10-19T16:05:05.805Z

cve-icon NVD

Status : Deferred

Published: 2026-10-18T12:17:15.200

Modified: 2026-10-19T21:14:14.150

Link: CVE-2026-112021

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-19T12:53:12Z

Weaknesses
  • CWE-122

    Heap-based Buffer Overflow