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AFFLIB CVE-2026-119601

| EUVDEUVD-2026-113938 MEDIUM
Out-of-bounds Write (CWE-787)
2026-10-30 VulnCheck GHSA-cmx5-359p-fw39
6.9
CVSS 4.0 · Vendor: VulnCheck
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Craft AFF image with page size not a multiple of sector size
  2. Delivery
    Deliver image into forensic workflow
  3. Exploit
    Examiner opens image in AFFLIB-based tool
  4. Execution
    Zero-fill loop writes past heap buffer in af_get_page()
  5. Impact
    Heap corruption crashes forensic tool

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, write limits
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires an attacker-supplied AFF (Advanced Forensic Format) image in which the page size is set larger than, and not an integer multiple of, the sector size; this triggers the sector zero-fill loop in af_get_page() to write past the heap buffer. The target must be a forensic tool or workflow using AFFLIB through 3.7.22 that parses the malicious image. Limiting factors: the attack is local (the crafted image must be processed on the victim system) and depends on user/operator interaction (an examiner opening or ingesting the untrusted image, per UI:P), with no authentication qualifier derivable beyond PR:N; it does not reach over the network and produces primarily a crash/denial-of-service of the forensic tool.

Impact

Signals point to a moderate, forensics-specific issue rather than a broad emergency. The CVSS 4.0 vector (AV:L/AC:L/AT:N/PR:N/UI:P) describes a local, low-complexity flaw that still requires passive user interaction - a forensic operator must open or process an attacker-supplied AFF image - and the impact is weighted toward availability (VA:H) with only low integrity impact (VI:L) and no confidentiality impact (VC:N). Per the evidence the outcome is heap corruption that crashes the tool; it is CWE-787 (out-of-bounds write), so memory corruption is confirmed, but the sources describe a crash, not demonstrated code execution - do not treat this as confirmed RCE. Exploitation status: no CISA KEV listing, so this is not confirmed actively exploited; a public PoC/write-up reference exists (hackmd analysis plus the VulnCheck advisory), but it is not verified as working exploit code. No EPSS score was provided in the input, so exploitation probability cannot be quantified here. The vuln.today decision label is 'this_month' - a scheduled-remediation priority, not act_now/emergency - which is consistent with the medium CVSS of 6.9 and the narrow, interaction-dependent attack surface. Net: a real but bounded bug for environments running AFFLIB-based forensic tooling, driven by denial-of-service against analysts processing untrusted images, not a widespread network-exploitable threat.

Exploit ScenarioDerived

An attacker crafts a malicious AFF forensic image whose page size is larger than and not a multiple of the sector size, then gets it into an investigation pipeline (e.g., evidence submitted for analysis or seized media). When a forensic examiner opens the image in a tool built on AFFLIB ≤3.7.22, af_get_page()'s sector zero-fill loop writes past the heap buffer, corrupting memory and crashing the tool. A public PoC reference/write-up exists but is not verified as working exploit code.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 30, 2026

Heap out-of-bounds write in AFFLIB through 3.7.22 during page reads: when a crafted AFF (Advanced Forensic Format) image declares a page size that is larger than and not an integer multiple of its sector size, the sector zero-fill loop in af_get_page() writes past the allocated heap buffer. The issue is local and requires a user or operator to open or ingest the untrusted image (UI:P), and the assessed impact is no confidentiality loss, limited integrity damage and high availability impact, meaning the practical outcome is a corrupted heap and crash of the forensic tool. A public technical write-up of the flaw exists but is not verified as working exploit code, and there is no CISA KEV entry; the vendor priority is 'this_month' rather than an emergency.

RemediationAI

No vendor-released patch or fixed version is identified in the available data; the upstream issue (https://github.com/sshock/AFFLIBv3/issues/61) and the project repository (https://github.com/sshock/AFFLIBv3) are the places to track for a corrected release, and the VulnCheck advisory (https://www.vulncheck.com/advisories/afflib-through-3.7.22-heap-out-of-bounds-write-in-af-get-page) summarizes the flaw. Because the defect is a geometry validation gap, the most direct compensating control is to pre-validate untrusted AFF headers before handing them to AFFLIB and reject any image whose page size is not an integer multiple of, or is larger than, its sector size - the trade-off being that unusual but legitimate images will be refused and require conversion or manual review. Where validation cannot be inserted, process untrusted images inside a sandboxed, low-privilege container or dedicated analysis VM with memory limits so a heap corruption only terminates the tool rather than affecting the examiner's host, at the cost of extra infrastructure and slower ingest. This matters in forensic workflows because the malicious image is the evidence itself, so acquisition and triage of untrusted images should be isolated from production case systems; the technical write-up at https://hackmd.io/@haindpwn/afflib-aff-get-page-sector-fill-oob-write documents the trigger for teams building their own validation checks.

Affected VersionsENISA

AFFLIB 0 ≤3.7.22

Affected Packages

euvd afflib no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

AFFLIBv3 (CPE cpe:2.3:a:sshock:afflib, through 3.7.22) implements the Advanced Forensic Format used to store disk images and forensic artifacts. The flaw is CWE-787 (out-of-bounds write) in af_get_page(), implemented in lib/afflib_pages.cpp around lines 309-315: the routine derives a sector zero-fill length from the image's declared page and sector sizes, and when page size is larger than and not a multiple of sector size, the computed fill length exceeds the buffer allocated for the page, producing a heap write past the end of the buffer. The CVSS:4.0 vector (AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H) and the independent CVSS:3.1 assessment (AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H) agree that this is a local, interaction-dependent memory-corruption issue with high availability impact and no confidentiality impact. The trigger is the geometry mismatch itself; no further exploitation precondition (e.g., a race or specific allocator state) is described in the available sources, and no evidence of code execution is presented - the observed outcome is heap corruption and a crash while parsing the image.

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Severity by source

Vendor (VulnCheck) PRIMARY 6.9 MEDIUM
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
vuln.today AI 6.1 MEDIUM

Local vector because a crafted file must be opened (AV:L, UI:R); no auth (PR:N); impact is a crash so A:H, minor memory corruption I:L, and no confidentiality (C:N).

3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H
4.0 AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
Passive
Vulnerable system: Confidentiality
None
Vulnerable system: Integrity
Low
Vulnerable system: Availability
High
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

DescriptionCVE.org

AFFLIB through 3.7.22 contains a heap out-of-bounds write vulnerability in af_get_page() that allows attackers to corrupt heap memory by supplying crafted AFF images with mismatched page and sector sizes. Attackers can set a page size larger than and not a multiple of the sector size, causing the sector zero-fill loop to write past the buffer and crash forensic tools.

Threat Intelligence Overview

EPSS Score
0.1%
Top 98% exploitable
Prevalence
Low
niche digital-forensics library, limited to forensic tooling environments
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.1%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

34
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +34
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.

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