Libjpeg
CVE-2021-39517
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A10:2025 - Mishandling of Exceptional Conditions
ASVS 5.0
V16 - Security Logging and Error Handling Null pointer safety, defensive checks
MITRE ATT&CK
1 technique across 1 tactic: Impact The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 6.5 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required. Public proof-of-concept exploit code is available. |
| Exploit ScenarioDerived | A remote attacker could crash the application by dereferencing a null pointer by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
An issue was discovered in libjpeg through 2020021. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Check pointers before dereferencing. Use static analysis tools to detect null pointer paths.
Affects your stack
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Technical ContextAI · show details
This vulnerability is classified as NULL Pointer Dereference (CWE-476), which allows attackers to crash the application by dereferencing a null pointer. An issue was discovered in libjpeg through 2020021. A NULL pointer dereference exists in the function BlockBitmapRequester::ReconstructUnsampled() located in blockbitmaprequester.cpp. It allows an attacker to cause Denial of Service. Affected products include: Jpeg Libjpeg. Version information: through 2020021..
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
An issue was discovered in libjpeg through 2020021. A NULL pointer dereference exists in the function BlockBitmapRequester::ReconstructUnsampled() located in blockbitmaprequester.cpp. It allows an attacker to cause Denial of Service.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
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.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A null pointer dereference occurs when a program attempts to access memory through a pointer that has been set to NULL (address 0x0).
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)NVD
An issue was discovered in libjpeg 9a and 9d. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitab
libjpeg commit 281daa9 was discovered to contain an infinite loop via the component Frame::ParseTrailer. Rated high seve
In IJG JPEG (aka libjpeg) from version 8 through 9c, jdhuff.c has an out-of-bounds array read for certain table pointers
libjpeg commit db33a6e was discovered to contain a heap buffer overflow via LineBitmapRequester::EncodeRegion at linebit
libjpeg commit db33a6e was discovered to contain a reachable assertion via BitMapHook::BitMapHook at bitmaphook.cpp. Rat
libjpeg commit 281daa9 was discovered to contain a segmentation fault via LineMerger::GetNextLowpassLine at linemerger.c
libjpeg commit 281daa9 was discovered to contain a segmentation fault via HuffmanDecoder::Get at huffmandecoder.hpp. Rat
There is an assertion failure in SingleComponentLSScan::ParseMCU in singlecomponentlsscan.cpp in libjpeg before 1.64 via
In libjpeg before 1.64, BitStream<false>::Get in bitstream.hpp has an assertion failure that may cause denial of service
An issue was discovered in libjpeg through 2020021. Rated medium severity (CVSS 6.5), this vulnerability is remotely exp
An issue was discovered in libjpeg through 2020021. Rated medium severity (CVSS 6.5), this vulnerability is remotely exp
An issue was discovered in libjpeg through 2020021. Rated medium severity (CVSS 6.5), this vulnerability is remotely exp
Exploit-DB