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Vulnerability record · CVE-2026-55209 · published 14 September 2026

CVE-2026-55209: Classic buffer overflow vulnerability

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.

9.8 CVSS 3.1 Critical EPSS 0.78% · top 45.9% CWE-120 · Classic buffer overflowCWE-125 · Out-of-bounds read Received
9.8CVSS 3.1 base score
0.78%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
6References
14 Sep 2026Last modified by NVD

Description

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.

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

References

LinkTags
https://github.com/equinor/resdata/commit/9f8fd6db472e0696080b768389914d60a453904f
https://github.com/equinor/resdata/commit/d3f45828e9413506b8e8160a9304f4b7b06dcefc
https://github.com/equinor/resdata/commit/ee8cc12b026d945df3077bc98e211ee45f80a433
https://github.com/equinor/resdata/pull/1166
https://github.com/equinor/resdata/releases/tag/6.2.9
https://github.com/equinor/resdata/security/advisories/GHSA-pr85-w493-9w3x

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Source: NIST National Vulnerability Database (record CVE-2026-55209), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.