EUVD-2026-64313
GHSA-cm34-rh84-36rf
Severity by source
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Local tool invoked by operator against crafted input (AV:L, UI:R, PR:N); heap overflow causes crash (A:H) with minimal integrity side-effect (I:L); no confidentiality impact.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
2DescriptionCVE.org
hashcat contains a heap-based buffer overflow (out-of-bounds write) in the outfile_write() function in src/outfile.c. When assembling output into a fixed-size buffer (HCBUFSIZ_LARGE, ~16 MB), the function sequentially appends the username, separator, hash, and plaintext via memcpy without validating that the accumulated length stays within the buffer capacity. When run with --username --show against a crafted hash file containing an oversized username that nearly fills the buffer, the total assembled output exceeds the buffer, causing a heap buffer overflow that can corrupt memory and crash the process.
AnalysisAI
Heap buffer overflow in hashcat through version 7.1.2 allows an attacker who controls a hash file to crash the process and corrupt heap memory when an operator runs hashcat with the --username --show flags. The outfile_write() function in src/outfile.c sequentially appends username, separator, hash, and plaintext into a fixed ~16 MB heap buffer (HCBUFSIZ_LARGE) via memcpy without tracking accumulated length against buffer capacity, enabling an out-of-bounds write. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Both --username and --show flags must be passed simultaneously to hashcat for the vulnerable code path in outfile_write() to execute. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 vector (AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N, score 6.9) accurately characterises this as a medium-severity local issue: attack vector is local, user interaction is required, and primary impact is availability (crash/memory corruption) with negligible confidentiality impact. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Update to a hashcat build incorporating upstream commit 68f56a2d8712867a8520bf4dcf07f6145c23df89, which is available at https://github.com/hashcat/hashcat/commit/68f56a2d8712867a8520bf4dcf07f6145c23df89. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Heap buffer overflow in hashcat's KeePass AESKDF/KDBX v4 cracking module (module_34301.c) exposes master branch builds a
Same weakness CWE-120 – Classic Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
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