Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 0.48% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2025
CVE-2025-0689High confidence
Grub2: udf: heap based buffer overflow in grub_udf_read_block() may lead to arbitrary code execution
Unknown · Unknown
7.8HighCVSS 3.1
Within 7 days
Fix not verifiedHigh technical severity; prioritise exposed affected systems while verifying vendor guidance.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:High, unchanged from published severity.unchanged
Compensating controls
- Restrict local access and enforce least privilege on affected hosts.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Unknown Unknown and falls inside the recorded affected range.
- Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Distribution package intelligence
6 package statesRelease-specific package status
Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
| Distribution release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Debian trixietrixie · source | grub2 | Vendor fix publishedDebian records a fixed source-package version for this release. | 2.12-6 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian bookwormbookworm · source | grub2 | Vendor fix publishedDebian records a fixed source-package version for this release. | 2.06-13+deb12u2 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian forkyforky · source | grub2 | Vendor fix publishedDebian records a fixed source-package version for this release. | 2.12-6 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian sidsid · source | grub2 | Vendor fix publishedDebian records a fixed source-package version for this release. | 2.12-6 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | grub2-signed | Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing. | Not published in this feed | Canonical Ubuntu Security ↗Source updated 5 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | grub2-unsigned | Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing. | Not published in this feed | Canonical Ubuntu Security ↗Source updated 5 Oct 2026 |
High technical severity; prioritise exposed affected systems while verifying vendor guidance.
Fix not verified01
What, why and how
When reading data from disk, the grub's UDF filesystem module utilizes the user controlled data length metadata to allocate its internal buffers. In certain scenarios, while iterating through disk sectors, it assumes the read size from the disk is always smaller than the allocated buffer size which is not guaranteed. A crafted filesystem image may lead to a heap-based buffer overflow resulting in critical data to be corrupted, resulting in the risk of arbitrary code execution by-passing secure boot protections.
What
When reading data from disk, the grub's UDF filesystem module utilizes the user controlled data length metadata to allocate its internal buffers. In certain scenarios, while iterating through disk sectors, it assumes the read size from the disk is always smaller than the allocated buffer size which is not guaranteed. A crafted filesystem image may lead to a heap-based buffer overflow resulting in critical data to be corrupted, resulting in the risk of arbitrary code execution by-passing secure boot protections.
Why
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.
How
An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may execute code or commands in the affected security context.
What
When reading data from disk, the grub's UDF filesystem module utilizes the user controlled data length metadata to allocate its internal buffers. In certain scenarios, while iterating through disk sectors, it assumes the read size from the disk is always smaller than the allocated buffer size which is not guaranteed. A crafted filesystem image may lead to a heap-based buffer overflow resulting in critical data to be corrupted, resulting in the risk of arbitrary code execution by-passing secure boot protections.
Why
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.
How
An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may execute code or commands in the affected security context.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- local access → Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') → execute code or commands in the affected security context
- Attack surface
- Local
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- Required interaction required
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Unchanged: impact remains within the vulnerable component's security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-120 ↗
CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow'). 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.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.- Post-exploitation / living off the land
- After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Fix not verified
- Affected
- ≤ 2.12
- Fixed
- No fixed version is explicitly recorded in the structured CVE data.
- Action
- No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
- Workaround
- No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04
Evidence and provenance
Published 3 Mar 2025 · Last source change 29 Jun 2026, 23:24 UTC · CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2025-5596
Product sourceUnavailable
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD modified after enrichment
Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.
Material change intelligence
View recent updates ↗What changed after publication
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.