dbcve.org
UclibcApplication

CVE-2022-30295

MEDIUM · 6.5 CVSS v3.1 Published 2022-05-06
Fix available
A fix is available. Upgrade to after 1.0.40 or later.
See remediation →
74/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

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 · unedited
uClibc-ng through 1.0.40 and uClibc through 0.9.33.2 use predictable DNS transaction IDs that may lead to DNS cache poisoning. This is related to a reset of a value to 0x2.

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 confidence

The uClibc and uClibc-ng DNS resolver implementations use predictable transaction IDs for DNS queries, making them vulnerable to DNS cache poisoning attacks. The vulnerability stems from a code path that resets a transaction ID value to 0x2, removing entropy from the DNS query identifier. An attacker could potentially forge DNS responses to redirect traffic by predicting the transaction ID.

MitigationUpdate uClibc-ng to version 1.0.41 or later, or apply vendor patches to uClibc 0.9.33.2. If patching is not immediately feasible, implement network-level defenses such as DNSSEC validation or DNS query source port randomization at upstream resolvers.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
UclibcApplication
Affected:<= 0.9.33.2
Uclibc NgApplication
Affected:<= 1.0.40

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify uClibc library version
    Run 'ldd <binary>' to list linked libraries, then use 'strings <libc> | grep 'uClibc'' or check the library file metadata to determine the exact version number
    Affected if The installed uClibc version is 0.9.33.2 or lower, or uClibc-ng version is 1.0.40 or lower
  2. Confirm DNS resolver is in use
    Review application functionality to determine if it performs DNS lookups (check for gethostbyname, getaddrinfo, or similar resolver calls)
    Affected if The application or system uses the uClibc DNS resolver for name resolution
  3. Inspect DNS transaction ID generation
    If source code is available, search for DNS ID generation routines and check for the pattern where transaction ID is hardcoded to 0x2 or uses low entropy
    Affected if The DNS resolver code resets or uses a predictable transaction ID value (such as 0x2) instead of random IDs for each query
  4. Check library build configuration
    Examine the uClibc build configuration file (.config) for DNS resolver settings, or use 'strings' on the library to search for DNS-related function names and their implementations
    Affected if The library was built with the standard DNS resolver and contains the vulnerable code path

You are affected if your system uses uClibc or uClibc-ng at version 0.9.33.2 or below (uClibc) or 1.0.40 or below (uClibc-ng) and performs DNS queries using the built-in resolver.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to a release after 1.0.40
Interim mitigation

Update uClibc-ng to version 1.0.41 or later, or apply vendor patches to uClibc 0.9.33.2. If patching is not immediately feasible, implement network-level defenses such as DNSSEC validation or DNS query source port randomization at upstream resolvers.

Recommended fix Moderate confidence

uClibc-ng: upgrade to 1.0.41 or later; uClibc: upgrade to a version newer than 0.9.33.2

  1. 1. Identify the specific uClibc or uClibc-ng library version currently in use in your build system or embedded device firmware.
  2. 2. For uClibc-ng: Upgrade to version 1.0.41 or later, which contains the fix for the predictable DNS transaction ID vulnerability.
  3. 3. For uClibc (non-ng): Upgrade to a version newer than 0.9.33.2 that addresses the DNS transaction ID predictability issue; if no newer stable release exists, consider migrating to uClibc-ng.
  4. 4. Rebuild the firmware or software stack that links against the uClibc library with the updated version.
  5. 5. Verify that the new library binary is correctly deployed and that DNS resolution still functions properly.
  6. 6. Test DNS cache poisoning resilience if possible, to confirm the random transaction IDs are being generated.
Caveat Minor: Ensure any custom DNS resolver configurations or patches are compatible with the new library version; some embedded systems may have toolchain dependencies that require adjustment.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Uclibc Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2022-30295 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-30295 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data