CVE-2017-12133
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 · uneditedUse-after-free vulnerability in the clntudp_call function in sunrpc/clnt_udp.c in the GNU C Library (aka glibc or libc6) before 2.26 allows remote attackers to have unspecified impact via vectors related to error path.
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 · moderate confidenceUse-after-free vulnerability in the clntudp_call function within sunrpc/clnt_udp.c of glibc versions prior to 2.26. The flaw exists in the error path handling of the UDP-based RPC client, where memory is freed but subsequently accessed, potentially allowing remote attackers to cause unspecified impact via crafted RPC requests.
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<= 2.25CVSS 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
- None
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/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 checksWork through these to decide whether this CVE applies to you.
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Check installed glibc versionRun 'ldd --version' or 'rpm -q glibc' or 'dpkg -l | grep libc6' to retrieve the glibc version installed on the systemAffected if The installed version is 2.25 or lower (e.g., 2.24, 2.23, 2.22, etc.)
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Verify if rpcbind service is activeRun 'systemctl status rpcbind' or 'systemctl status rpcbind.socket' on systemd systems, or 'service rpcbind status' on SysV init systemsAffected if The rpcbind service is running and accepting UDP-based RPC requests
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Check for listening UDP RPC portsRun 'ss -ulnp' or 'netstat -ulnp' and look for port 111 (rpcbind) or other RPC-related UDP listenersAffected if Any RPC service is bound to a UDP port and actively listening
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Identify processes using UDP RPC clientsRun 'ss -up' or examine /proc/net/udp to see which processes have open UDP sockets that may be used for RPC communicationAffected if Applications are making outbound UDP-based RPC calls to remote services
You are affected if glibc version is 2.25 or lower AND any SUN RPC client functionality using UDP is actively being used on the system, since the use-after-free only triggers during UDP RPC client error path handling.
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.
From vendor dataUpgrade glibc to version 2.26 or later to obtain the patched version. In environments where immediate patching is not feasible, restrict or disable SUN RPC services (rpcbind) and filter RPC traffic at network boundaries to reduce exposure.
- Consultation4.0 h
- Implementation8.0 h
- Testing12.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2017-12133 — 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-2017-12133 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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- Version or environment caveats, and links to real fixes
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