Every CVE Search/ Get API key

CVE-2021-30500

Null pointer dereference was found in upx PackLinuxElf::canUnpack() in p_lx_elf.cpp,in version...

7.8 HighFix available

Null pointer dereference was found in upx PackLinuxElf::canUnpack() in p_lx_elf.cpp,in version UPX 4.0.0. That allow attackers to execute arbitrary code and cause a denial of service via a crafted file.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
Low
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

1.23%Down 0.6 points since May 27, 2021
90%50%10%1%

What each source reports

NVD Score used 7.8

Null pointer dereference was found in upx PackLinuxElf::canUnpack() in p_lx_elf.cpp,in version UPX 4.0.0. That allow attackers to execute arbitrary code and cause a denial of service via a crafted file.

Record
CVE-2021-30500
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS 2.0
6.8 MediumAV:N/AC:M/Au:N/C:P/I:P/A:P
Weakness
CWE-476
Updated
2026-11-02
CVE List No score

Null pointer dereference was found in upx PackLinuxElf::canUnpack() in p_lx_elf.cpp,in version UPX 4.0.0. That allow attackers to execute arbitrary code and cause a denial of service via a crafted file.

Record
CVE-2021-30500
Weakness
CWE-476
Updated
2026-11-02
EUVDEUVD-2021-17421 No score

Null pointer dereference was found in upx PackLinuxElf::canUnpack() in p_lx_elf.cpp,in version UPX 4.0.0. That allow attackers to execute arbitrary code and cause a denial of service via a crafted file.

Record
EUVD-2021-17421
Updated
2026-11-03
GitHub AdvisoriesGHSA-5339-45c2-mh5v 7.8

Null pointer dereference was found in upx PackLinuxElf::canUnpack() in p_lx_elf.cpp,in version...

Null pointer dereference was found in upx PackLinuxElf::canUnpack() in p_lx_elf.cpp,in version UPX 4.0.0. That allow attackers to execute arbitrary code and cause a denial of service via a crafted file.

Record
GHSA-5339-45c2-mh5v
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness
CWE-476
Updated
2026-11-02
OSVALPINE-CVE-2021-30500 7.8

Null pointer dereference was found in upx PackLinuxElf::canUnpack() in p_lx_elf.cpp,in version UPX 4.0.0. That allow attackers to execute arbitrary code and cause a denial of service via a crafted file.

Record
ALPINE-CVE-2021-30500
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated
2026-11-03
OSVBELL-CVE-2021-30500 7.8

CVE-2021-30500 does not affect BellSoft software

Record
BELL-CVE-2021-30500
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated
2026-11-02
Show 4 moreShow less
OSV 7.8

Null pointer dereference was found in upx PackLinuxElf::canUnpack() in p_lx_elf.cpp,in version UPX 4.0.0. That allow attackers to execute arbitrary code and cause a denial of service via a crafted file.

Record
CVE-2021-30500
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2021-30500 7.8

Null pointer dereference was found in upx PackLinuxElf::canUnpack() in p_lx_elf.cpp,in version UPX 4.0.0. That allow attackers to execute arbitrary code and cause a denial of service via a crafted file.

Record
DEBIAN-CVE-2021-30500
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2021-30500 7.8

Null pointer dereference was found in upx PackLinuxElf::canUnpack() in p_lx_elf.cpp,in version UPX 4.0.0. That allow attackers to execute arbitrary code and cause a denial of service via a crafted file.

Record
UBUNTU-CVE-2021-30500
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVopenSUSE-SU-2023:0088-1 No score

Security update for upx

upx was updated to fix the following issues:

Update to release 4.0.2

  • Fix unpack of ELF x86-64 that failed with 'CantUnpackException: corrupt b_info'
  • Resolve SEGV on PackLinuxElf64::invert_pt_dynamic
  • CVE-2021-30500: Fixed Null pointer dereference in PackLinuxElf:canUnpack() in p_lx_elf.cpp
  • CVE-2021-30501: Fixed Assertion abort in function MemBuffer:alloc()
  • CVE-2021-43311: Fixed Heap-based buffer overflow in PackLinuxElf32:elf_lookup() at p_lx_elf.cpp
  • CVE-2021-43312: Fixed Heap-based buffer overflow in PackLinuxElf64:invert_pt_dynamic at p_lx_elf.cpp:5239
  • CVE-2021-43313: Fixed Heap-based buffer overflow in PackLinuxElf32:invert_pt_dynamic at p_lx_elf.cpp:1688
  • CVE-2021-43314: Fixed Heap-based buffer overflows in PackLinuxElf32:elf_lookup() at p_lx_elf.cp
  • CVE-2021-43315: Fixed Heap-based buffer overflows in PackLinuxElf32:elf_lookup() at p_lx_elf.cp
  • CVE-2021-43316: Fixed Heap-based buffer overflow in func get_le64()
  • CVE-2021-43317: Fixed Heap-based buffer overflows in PackLinuxElf64:elf_lookup() at p_lx_elf.cp
  • CVE-2023-23456: Fixed heap-buffer-overflow in PackTmt:pack()
  • CVE-2023-23457: Fixed SEGV on PackLinuxElf64:invert_pt_dynamic() in p_lx_elf.cpp
Record
openSUSE-SU-2023:0088-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
upx
Alpine:v3.17
 before 4.0.0-r0
4.0.0-r0
upx
Alpine:v3.18
 before 4.0.0-r0
4.0.0-r0
upx
Alpine:v3.19
 before 4.0.0-r0
4.0.0-r0
upx
Alpine:v3.20
 before 4.0.0-r0
4.0.0-r0
upx
Alpine:v3.21
 before 4.0.0-r0
4.0.0-r0
upx
Alpine:v3.22
 before 4.0.0-r0
4.0.0-r0
upx
Alpine:v3.23
 before 4.0.0-r0
4.0.0-r0
upx
Alpine:v3.24
 before 4.0.0-r0
4.0.0-r0
upx-ucl
Debian:13
 before 4.2.2-1
4.2.2-1
upx-ucl
Debian:14
 before 4.2.2-1
4.2.2-1
Show 10 moreShow less
Affected packages
PackageAffectedFixed
upx-ucl
Ubuntu:16.04:LTS
 All versions, plus listed versions
3.91-1
 None known
upx-ucl
Ubuntu:18.04:LTS
 All versions, plus listed versions
3.94-23.94-33.94-4
 None known
upx-ucl
Ubuntu:20.04:LTS
 All versions, plus listed versions
3.95-23.95-2build1
 None known
upx-ucl
Ubuntu:22.04:LTS
 All versions, plus listed versions
3.96-23.96-3
 None known
upx-ucl
Ubuntu:24.04:LTS
 All versions, plus listed versions
3.96-34.2.2-3
 None known
upx-ucl
Ubuntu:25.10
 All versions, plus listed versions
4.2.4-14.2.4-1.1
 None known
upx-ucl
Ubuntu:26.10
 All versions, plus listed versions
4.2.4-1.1build1
 None known
upx-ucl
Ubuntu:26.04:LTS
 All versions, plus listed versions
4.2.4-1.14.2.4-1.1build1
 None known
upx
SUSE:Package Hub 15 SP4
From an advisory covering 12 CVEs
 before 4.0.2-bp154.4.6.1
4.0.2-bp154.4.6.1
upx
openSUSE:Leap 15.4
From an advisory covering 12 CVEs
 before 4.0.2-bp154.4.6.1
4.0.2-bp154.4.6.1

History

History
RecordedChangedSources
affected, facts
affected, aliases, referencesOSV
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-30500 is a high vulnerability (CVSS 7.8) in Upx, published May 26, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.23%, the 69th percentile. Fixed in upx 4.0.0-r0.

References

Show 29 moreShow less
Pages All vulnerabilities Browse Docs Sources Guide Get API key
MoveEnter Open