CVE-2021-39517
An issue was discovered in libjpeg through 2020021. A NULL pointer dereference exists in the...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2021-39517- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:N/A:P - Weakness
- CWE-476
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2021-39517- Updated
- 2026-11-02
EUVDEUVD-2021-25874 No score
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.
- Record
EUVD-2021-25874- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-26c8-846h-xfjj No score
An issue was discovered in libjpeg through 2020021. A NULL pointer dereference exists in the...
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.
- Record
GHSA-26c8-846h-xfjj- Weakness
- CWE-476
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2021-39517- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2021-39517
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.
- Record
DEBIAN-CVE-2021-39517- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-39517
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.
- Record
UBUNTU-CVE-2021-39517- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
libjpegDebian:12 |
before 0.0~git20200925.f145908-1 | 0.0~git20200925.f145908-1 |
libjpegDebian:13 |
before 0.0~git20200925.f145908-1 | 0.0~git20200925.f145908-1 |
libjpegDebian:14 |
before 0.0~git20200925.f145908-1 | 0.0~git20200925.f145908-1 |
libjpeg6bUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 1:6b2-21:6b2-2ubuntu0.1~esm1 |
None known |
libjpegUbuntu:20.04:LTS |
All versions, plus listed versions 0.0~git20190821.87636f3b26b4-10.0~git20190821.87636f3b26b4-1.1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-39517 is a medium vulnerability (CVSS 6.5) in Jpeg Libjpeg, published September 20, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.86%, the 58th percentile. Fixed in libjpeg 0.0~git20200925.f145908-1.