Equinor resdata up to 6.2.8 GRDECL Parser rd_kw_grdecl.cpp rd_grid_alloc_GRDECL_kw__ buffer overflow

Summaryinfo

A vulnerability classified as critical has been found in Equinor resdata up to 6.2.8. This impacts the function rd_grid_alloc_GRDECL_kw__ of the file lib/resdata/rd_kw_grdecl.cpp of the component GRDECL Parser. Performing a manipulation results in buffer overflow. This vulnerability is identified as CVE-2026-55209. The attack can be initiated remotely. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Equinor resdata up to 6.2.8. This affects the function rd_grid_alloc_GRDECL_kw__ of the file lib/resdata/rd_kw_grdecl.cpp of the component GRDECL Parser. The manipulation with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

resdata is software for reading and writing result files from the Eclipse reservoir simulator. Prior to 6.2.9, resdata insufficiently validates numeric fields, grid dimensions, keyword sizes, and array indexes while parsing untrusted GRDECL files in lib/resdata/rd_kw_grdecl.cpp and lib/resdata/rd_grid.cpp. Malformed COORD, ZCORN, CORSNUM, ACTNUM, or MAPAXES data can reach rd_grid_alloc_GRDECL_kw__ with inconsistent lengths, while unbounded floating-point conversion can exceed the intended parser buffer. In a network service that accepts untrusted GRDECL files, these conditions can cause a classic buffer overflow, out-of-bounds reads, invalid array access, NULL pointer dereference, memory corruption, or service termination. This issue is fixed in version 6.2.9.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-55209 since 06/16/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 6.2.9 eliminates this vulnerability.

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Productinfo

Vendor

• Equinor

Name

• resdata

Version

• 6.2.0
• 6.2.1
• 6.2.2
• 6.2.3
• 6.2.4
• 6.2.5
• 6.2.6
• 6.2.7
• 6.2.8

Website

• Product: https://github.com/equinor/resdata/

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