CVE-2026-5759: Double Free (CVSS 9.8)

Description

A double free and use-after-free vulnerability in the RdbLoadDeletedNodes function of the RDB graph decoders (src/serializers/decoders/*/decode_graph_entities.c) in FalkorDB before 4.18.1 allows a remote attacker who can issue Redis replication commands (for example, against an instance with no password configured) to cause a denial of service or execute arbitrary code in the redis-server process by supplying a crafted RDB stream whose deleted-nodes buffer length is not a multiple of sizeof(NodeID). The length check relies on ASSERT(), which is compiled out in release builds, so the function continues after freeing the buffer, reading it and freeing it a second time.

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CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0055

Probability of exploitation

0.45%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-415 CWE-415

CWE-416 Use After Free

References

Other References

https://github.com/FalkorDB/FalkorDB/commit/523d98ac7ffe99f11a9c95c258025c235f0dff4c https://github.com/FalkorDB/FalkorDB/pull/1843 https://github.com/FalkorDB/FalkorDB/releases/tag/v4.18.1

Frequently Asked Questions

What is CVE-2026-5759? +

A double free and use-after-free vulnerability in the RdbLoadDeletedNodes function of the RDB graph decoders (src/serializers/decoders/*/decode_graph_entities.c) in FalkorDB before 4.18.1 allows a remote attacker who can issue Redis replication commands (for example, against an instance with no password configured) to cause a denial of service or execute arbitrary code in the redis-server process by supplying a crafted RDB stream whose deleted-nodes buffer length is not a multiple of sizeof(NodeID). The length check relies on ASSERT(), which is compiled out in release builds, so the function continues after freeing the buffer, reading it and freeing it a second time. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-5759? +

CVE-2026-5759 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0055, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-5759? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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