Is CVE-2026-18313 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-18313 being exploited in the wild.

How severe is CVE-2026-18313?

Medium severity, with a CVSS score of 4.3, published 5 September 2026.

Is there a fix for CVE-2026-18313?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-18313 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-18313?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-18313: libpcap rpcapd memory leak in daemon_unpackapplyfilter

CVE-2026-18313 · Severity: medium · CVSS 4.3 · Published 2026-09-05

rpcapd is the remote packet capture daemon shipped with libpcap, used for capturing network traffic over a network connection. A flaw causes the daemon to leak up to 65 KB of memory per request message from a client without ever freeing it; an attacker can trigger memory exhaustion and cause a denial of service by sending repeated malicious requests.

Quick answers

Is CVE-2026-18313 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-18313 being exploited in the wild.
How severe is CVE-2026-18313?: Medium severity, with a CVSS score of 4.3, published 5 September 2026.
Which products and versions are affected?: The Tcpdump Group libpcap.
Is there a fix for CVE-2026-18313?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-18313 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-18313?: Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A memory leak exists in the daemon_unpackapplyfilter() function in rpcapd, where temporary buffers up to 65536 bytes (8192 BPF instructions) allocated during processing of RPCAP_MSG_UPDATEFILTER_REQ and RPCAP_MSG_STARTCAP_REQ messages are never freed. The vulnerability occurs in the daemon.c component and is triggered by network requests from any client that establishes a connection. A malicious attacker can repeatedly send such messages to exhaust server memory and cause denial of service. The fix involves ensuring allocated memory is properly freed after use, and a patch has been committed to the libpcap repository.

Affected products

The Tcpdump Group libpcap

Timeline

2026-09-05: disclosed

References

https://github.com/the-tcpdump-group/libpcap/commit/f9775af1a0ec76db60c7213241e6b48f1be10ac7

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