NaviServer 4.99.4 to 4.99.19 allows denial of service due to the nsd/driver.c ChunkedDecode function not properly validating the length of…

published 2020-05-16 6y ago modified 2026-06-17 4mo ago also EUVD-2020-5387

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.4%; EPSS 1.4% chance of exploitation in 30 days, percentile 73%
public exploits: 0; none known

NaviServer 4.99.4 to 4.99.19 allows denial of service due to the nsd/driver.c ChunkedDecode function not properly validating the length of a chunk. A remote attacker can craft a chunked-transfer request that will result in a negative value being passed to memmove via the size parameter, causing the process to crash.

Patch / fix

links 1

bitbucket.org/naviserver/naviserver@a5c3079 commit

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Exploit prediction

1.44% chance of exploitation in the next 30 days, higher than 73% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness

CWE-20 Improper Input Validation
CWE-787 Out-of-bounds Write

References

bitbucket.org /naviserver/naviserver/commits/a5c3079f1d8996d5f34c9384a440acf3519ca3bb
patch, third-party-advisory
sourceforge.net /p/naviserver/bugs/89/
permissions-required, third-party-advisory

Sources

CVE List CVE-2020-13111
NVD CVE-2020-13111

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