CVE-2026-112021

snac2 before 2.93 Heap-Based Buffer Overflow via JSON Parser _xs_json_load_lexer()

Published Oct 18, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

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

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

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Oct 19, 2026, 4:05 PM
Reserved
Oct 18, 2026, 1:24 AM
Status
Deferred
Published
Oct 18, 2026, 12:17 PM
Modified
Oct 19, 2026, 9:14 PM