CVE-2024-46304
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 in libcoap v4.3.5-rc2 and below allows a remote attacker to cause a denial of service via the coap_handle_request_put_block function in src/coap_block.c.
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 confidenceA NULL pointer dereference vulnerability in libcoap versions 4.3.5-rc2 and earlier in the coap_handle_request_put_block function in src/coap_block.c allows remote attackers to cause denial of service by sending specially crafted CoAP block transfer requests that trigger the NULL dereference.
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
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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.
-
Identify installed libcoap versionRun 'dpkg -l libcoap-*' or 'rpm -qa | grep libcoap' to list installed libcoap packages. Alternatively, check the library file: 'strings /usr/lib/x86_64-linux-gnu/libcoap*.so | grep -i version' or check build info if linked statically.Affected if The version is 4.3.5-rc2 or earlier (any 4.x version up to and including 4.3.5-rc2).
-
Locate CoAP services using libcoapCheck for running CoAP daemons or services: 'ps aux | grep -i coap' and 'netstat -tulpn | grep -i coap' or 'ss -tulpn | grep -i coap' to identify processes listening on CoAP ports (typically 5683/udp).Affected if A CoAP server or client process is running that links against a vulnerable libcoap version.
-
Verify block transfer handling is enabledExamine the CoAP service configuration for block transfer support. Check config files or command-line flags for options like '--block' or examine the service startup script for block-wise transfer parameters.Affected if The CoAP service has block transfer handling enabled (this is the code path containing the vulnerable function coap_handle_request_put_block).
-
Confirm exposure to networkReview firewall rules and network exposure: 'iptables -L -n' or check if the CoAP port (5683/udp by default) is bound to a public or accessible network interface rather than localhost only.Affected if The CoAP service is accessible over the network (not bound to 127.0.0.1 only) allowing remote attackers to send crafted block transfer requests.
You are affected if you run a CoAP server or service that uses libcoap version 4.3.5-rc2 or earlier, has block transfer handling enabled, and is network-accessible.
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 dataUpdate libcoap to a version newer than 4.3.5-rc2 once available, or apply vendor-supplied patches. As a temporary workaround, consider network-level filtering or rate limiting of CoAP traffic to reduce exposure.
- Consultation3.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,832.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-46304 — 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-2024-46304 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
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.
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.
- 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