CVE-2026-55209
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.
What this means for your business
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.4% chance of attack attempts being seen in the next 30 days, ranking above 35% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
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Scoring
- CVSS
- 9.8 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness
- CWE-120
- Assigned by
- security-advisories@github.com
Dates
- Published
- 2026-09-14
- Last modified
- 2026-09-14
- Sources
- NVD
References
- 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