NetSurf libnsbmp up to 0.1.7 ICO File bmp_decode_mask out-of-bounds

Summaryinfo

A vulnerability, which was classified as critical, has been found in NetSurf libnsbmp up to 0.1.7. Affected by this vulnerability is the function bmp_decode_mask of the component ICO File Handler. The manipulation leads to out-of-bounds. This vulnerability is uniquely identified as CVE-2026-111139. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in NetSurf libnsbmp up to 0.1.7 and classified as critical. This issue affects the function bmp_decode_mask of the component ICO File Handler. The manipulation with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

NetSurf libnsbmp through 0.1.7 contains an out-of-bounds read vulnerability in bmp_decode_mask() that allows attackers to read one byte past the image buffer by supplying crafted ICO files. Attackers can provide an ICO whose inner bitmap width is not a multiple of 8, causing a heap over-read that can crash applications calling bmp_decode().

It is possible to read the advisory at hackmd.io. The identification of this vulnerability is CVE-2026-111139 since 10/15/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/15/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• NetSurf

Name

• libnsbmp

Version

• 0.1.0
• 0.1.1
• 0.1.2
• 0.1.3
• 0.1.4
• 0.1.5
• 0.1.6
• 0.1.7

CPE 2.3info

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CPE 2.2info

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