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CVE-2020-8244: Remote Memory Exposure in bl

6.5

CVSS Score
3.1

Basic Information

EPSS Score
0.58011%
Published
9/2/2020
Updated
2/1/2023
KEV Status
No
Technology
TechnologyJavaScript

Technical Details

CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Package NameEcosystemVulnerable VersionsFirst Patched Version
blnpm= 3.0.03.0.1
blnpm>= 4.0.0, < 4.0.34.0.3
blnpm< 1.2.31.2.3
blnpm>= 2.0.0, < 2.2.12.2.1

Vulnerability Intelligence
Miggo AIMiggo AI

Miggo AIRoot Cause Analysis

The vulnerability stems from two key issues: 1) consume() accepting negative values without validation, corrupting the BufferList's state. 2) copy() failing to truncate the destination buffer properly, exposing uninitialized memory. The patches added input validation in consume() (via Math.trunc() and positive checks) and a safeguard in copy() to slice the buffer to the actual copied length. The test cases explicitly target these scenarios by passing negative values to consume() and checking for memory exposure via slice().

Vulnerable functions

Only Mi**o us*rs **n s** t*is s**tion

WAF Protection Rules

WAF Rule

* *u***r ov*r-r*** vuln*r**ility *xists in *l <*.*.*, <*.*.*, <*.*.*, *n* <*.*.* w*i** *oul* *llow *n *tt**k*r to supply us*r input (*v*n typ**) t**t i* it *n*s up in *onsum*() *r*um*nt *n* **n ***om* n***tiv*, t** *u***rList st*t* **n ** *orrupt**,

Reasoning

T** vuln*r**ility st*ms *rom two k*y issu*s: *) `*onsum*()` ****ptin* n***tiv* v*lu*s wit*out v*li**tion, *orruptin* t** `*u***rList`'s st*t*. *) `*opy()` **ilin* to trun**t* t** **stin*tion *u***r prop*rly, *xposin* uniniti*liz** m*mory. T** p*t***s