CVE-2026-88831
MediumCVSS 5.3Exploitation Probability (EPSS)
Low risk9th percentile - higher than 9% of all known CVEs
Summary
BusyBox httpd IP deny rules with invalid CIDR prefix lengths fail open, leaving a parsed IP with a zeroed mask so the rule matches no clients. This may result in failure to block unwanted addresses.
Risk Assessment
The vulnerability may allow bypassing IP deny rules and accessing protected resources from IP addresses that should be blocked. Systems with IP deny rules in httpd are at risk.
Recommendation
Update BusyBox to a patched version. Verify the correctness of CIDR rules in the httpd configuration and avoid invalid prefixes.
Other vulnerabilities in BusyBox
See all- CVE-2017-16544High
In the add_match function in libbb/lineedit.c in BusyBox through 1.27.2, the tab autocomplete feature does not sanitize filenames, potentially leading to executing any escape sequences in the terminal.
- CVE-2011-5325High
Directory traversal vulnerability in the BusyBox implementation of tar before version 1.22.0 v5 allows remote attackers to point to files outside the current working directory via a symlink.
- CVE-2016-2147High
Integer overflow in the DHCP client (udhcpc) in BusyBox before version 1.25.0 allows remote attackers to cause a denial of service (crash) via a malformed RFC1035-encoded domain name, leading to an out-of-bounds heap write.
- CVE-2016-6301High
The recv_and_process_client_pkt function in networking/ntpd.c in busybox allows remote attackers to cause a denial of service via a forged NTP packet, triggering a communication loop.
- CVE-2022-48174Critical
A stack overflow vulnerability exists in ash.c:6030 in busybox before version 1.35. In the Internet of Vehicles environment, it can be exploited from command execution to arbitrary code execution.
- CVE-2026-88840Medium
BusyBox TLS get_client_hello() reads past the end of the input buffer when parsing a truncated ClientHello message. This can result in an out-of-bounds read.
- CVE-2026-88839Medium
BusyBox passwd/group tokenize() references a stale endpoint pointer after trimming, causing an out-of-bounds write of heap pointers. This can lead to memory corruption.
- CVE-2026-88837Medium
BusyBox httpd treats yescrypt ($y$) password hashes as plaintext during Basic Authentication, inverting the authentication check. This may allow unauthorized access.
- CVE-2026-88835Medium
BusyBox dpkg read_package_field() steps past a NUL terminator on malformed .deb packages, causing an out-of-bounds heap read. This may lead to data disclosure or a crash.
- CVE-2026-88832High
BusyBox romfs volume ID parsing uses unbounded strlen on attacker-controlled metadata, causing a heap buffer overflow when processing crafted filesystem images.
Original NVD description (English source)
BusyBox httpd IP deny rules with invalid CIDR prefix lengths fail open, leaving a parsed IP with a zeroed mask so the rule matches no clients.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

