CVE-2025-0696
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA NULL Pointer Dereference vulnerability in Cesanta Frozen versions less than 1.7 allows an attacker to induce a crash of the component embedding the library by supplying a maliciously crafted JSON as input.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceCesanta Frozen versions before 1.7 contain a NULL pointer dereference vulnerability in their JSON parsing component. When the library processes a maliciously crafted JSON input, it dereferences a NULL pointer, causing a crash of the application hosting the library.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Cesanta Frozen library usageSearch for library files (libfrozen.a, libfrozen.so, frozen.h) in your project dependencies, or grep for '#include "frozen.h"' or '#include <frozen.h>' in source codeAffected if The library files or headers are found in your environment
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Determine installed Frozen versionCheck the library version through package manager (npm list, pip show, cargo tree), or inspect frozen.h for FROZEN_VERSION macro, or check CHANGELOG/README for version stringAffected if The version is 1.6 or earlier, or no version is displayed (indicating older release)
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Verify JSON parsing is invokedSearch code for calls to json_parse(), parse_json(), or similar Frozen JSON functions; also check for any JSON endpoint, file parser, or API that processes external JSON inputAffected if Your code calls Frozen JSON parsing functions on untrusted or external input
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Check for NULL handling in JSON codeReview your JSON parsing error handling - look for absence of NULL checks after json_parse() return values, or absence of try-catch around JSON operationsAffected if The code does not validate json_parse() return values before using them
You are affected if Cesanta Frozen version 1.6 or earlier is in use and your application processes external JSON input through the library's parsing functions.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpgrade to Cesanta Frozen version 1.7 or later, which contains the fix for this vulnerability.
Cesanta Frozen version 1.7 or later
- 1. Identify all instances of the Cesanta Frozen library in your codebase or dependencies.
- 2. Check the current version of Cesanta Frozen being used (versions prior to 1.7 are vulnerable).
- 3. Upgrade Cesanta Frozen to version 1.7 or later, which contains the fix for the NULL pointer dereference vulnerability.
- 4. Rebuild and recompile any components that embed or link to the Cesanta Frozen library.
- 5. Test the updated component with various JSON inputs, including edge cases, to verify the vulnerability is mitigated and no regressions are introduced.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-0696 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-0696 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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