Every CVE Search/ Get API key

CVE-2026-31967

HTSlib CRAM reader has out-of-bounds read due to improper validation of input

6.9 MediumFix available

HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. In the cram_decode_slice() function called while reading CRAM records, the value of the mate reference id field was not validated. Later use of this value, for example when converting the data to SAM format, could result in the out of bounds array reads when looking up the corresponding reference name. If the array value obtained also happened to be a valid pointer, it would be interpreted as a string and an attempt would be made to write the data as part of the SAM record. This bug may allow information about program state to be leaked. It may also cause a program crash through an attempt to access invalid memory. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
None
Availability
Low

Exploit likelihood

0.47%Up 0.5 points since Mar 19, 2026
90%50%10%1%

What each source reports

CVE List Score used 6.9

HTSlib CRAM reader has out-of-bounds read due to improper validation of input

HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. In the cram_decode_slice() function called while reading CRAM records, the value of the mate reference id field was not validated. Later use of this value, for example when converting the data to SAM format, could result in the out of bounds array reads when looking up the corresponding reference name. If the array value obtained also happened to be a valid pointer, it would be interpreted as a string and an attempt would be made to write the data as part of the SAM record. This bug may allow information about program state to be leaked. It may also cause a program crash through an attempt to access invalid memory. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue.

Record
CVE-2026-31967
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N
Weakness
CWE-125, CWE-129
Updated
2026-11-02
EUVDEUVD-2026-12938 6.9

HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. In the cram_decode_slice() function called while reading CRAM records, the value of the mate reference id field was not validated. Later use of this value, for example when converting the data to SAM format, could result in the out of bounds array reads when looking up the corresponding reference name. If the array value obtained also happened to be a valid pointer, it would be interpreted as a string and an attempt would be made to write the data as part of the SAM record. This bug may allow information about program state to be leaked. It may also cause a program crash through an attempt to access invalid memory. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue.

Record
EUVD-2026-12938
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N
Updated
2026-11-02
NVD 6.9

HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. In the cram_decode_slice() function called while reading CRAM records, the value of the mate reference id field was not validated. Later use of this value, for example when converting the data to SAM format, could result in the out of bounds array reads when looking up the corresponding reference name. If the array value obtained also happened to be a valid pointer, it would be interpreted as a string and an attempt would be made to write the data as part of the SAM record. This bug may allow information about program state to be leaked. It may also cause a program crash through an attempt to access invalid memory. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue.

Record
CVE-2026-31967
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Weakness
CWE-125, CWE-129
Updated
2026-11-02
OSV 6.9

HTSlib CRAM reader has out-of-bounds read due to improper validation of input

HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. In the cram_decode_slice() function called while reading CRAM records, the value of the mate reference id field was not validated. Later use of this value, for example when converting the data to SAM format, could result in the out of bounds array reads when looking up the corresponding reference name. If the array value obtained also happened to be a valid pointer, it would be interpreted as a string and an attempt would be made to write the data as part of the SAM record. This bug may allow information about program state to be leaked. It may also cause a program crash through an attempt to access invalid memory. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue.

Record
CVE-2026-31967
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N
Weakness
CWE-125, CWE-129
Updated
2026-11-02
OSVDEBIAN-CVE-2026-31967 9.1

HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. In the cram_decode_slice() function called while reading CRAM records, the value of the mate reference id field was not validated. Later use of this value, for example when converting the data to SAM format, could result in the out of bounds array reads when looking up the corresponding reference name. If the array value obtained also happened to be a valid pointer, it would be interpreted as a string and an attempt would be made to write the data as part of the SAM record. This bug may allow information about program state to be leaked. It may also cause a program crash through an attempt to access invalid memory. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue.

Record
DEBIAN-CVE-2026-31967
CVSS 3.1
9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2026-31967 6.9

HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. In the cram_decode_slice() function called while reading CRAM records, the value of the mate reference id field was not validated. Later use of this value, for example when converting the data to SAM format, could result in the out of bounds array reads when looking up the corresponding reference name. If the array value obtained also happened to be a valid pointer, it would be interpreted as a string and an attempt would be made to write the data as part of the SAM record. This bug may allow information about program state to be leaked. It may also cause a program crash through an attempt to access invalid memory. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue.

Record
UBUNTU-CVE-2026-31967
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N
CVSS 3.1
9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
htslib
Debian:12
All versions, plus listed versions
1.16+ds-31.17+ds-0+exp11.17+ds-11.18+ds-0+exp11.18+ds-1
Show 15 moreShow less
1.19+ds-0+exp01.19+ds-11.19+ds-1+exp11.19+ds-1.11.20+ds-11.20+ds-21.21+ds-0+exp11.21+ds-0+exp21.21+ds-11.22.1+ds-11.22.1+ds-21.22.1+ds2-11.24-11.24-21.24-3
None known
htslib
Debian:13
All versions, plus listed versions
1.21+ds-11.22.1+ds-11.22.1+ds-21.22.1+ds2-11.24-11.24-21.24-3
None known
htslib
Debian:14
before 1.24-2, plus listed versions
1.21+ds-11.22.1+ds-11.22.1+ds-21.22.1+ds2-11.24-1
1.24-2
htslib
Ubuntu:Pro:14.04:LTS
All versions, plus listed versions
0.2.0~rc3-10.2.0~rc3-1ubuntu0.1~esm1
None known
htslib
Ubuntu:Pro:16.04:LTS
All versions, plus listed versions
1.2.1-11.2.1-21.2.1-2ubuntu11.2.1-2ubuntu1+esm1
None known
htslib
Ubuntu:Pro:18.04:LTS
All versions, plus listed versions
1.5-11.5-4ubuntu11.6-3ubuntu11.6-41.6-4build11.7-21.7-2ubuntu0.1~esm1
None known
htslib
Ubuntu:20.04:LTS
All versions, plus listed versions
1.9-101.9-111.9-121.10.2-2ubuntu11.10.2-2ubuntu21.10.2-31.10.2-3ubuntu0.1
None known
htslib
Ubuntu:22.04:LTS
All versions, plus listed versions
1.13+ds-21.13+ds-2build1
None known
htslib
Ubuntu:24.04:LTS
All versions, plus listed versions
1.17+ds-11.18+ds-11.19+ds-1.1build21.19+ds-1.1build3
None known
htslib
Ubuntu:25.10
All versions, plus listed versions
1.21+ds-1
None known
htslib
Ubuntu:26.10
All versions, plus listed versions
1.22.1+ds2-11.22.1+ds2-1build1
None known
htslib
Ubuntu:26.04:LTS
All versions, plus listed versions
1.21+ds-11.22.1+ds2-1
None known

History

History
RecordedChangedSources
first indexedCVE List, EUVD, NVD, OSV

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

In short

CVE-2026-31967 is a medium vulnerability (CVSS 6.9) in Htslib, published March 18, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.47%, the 41st percentile. Fixed in htslib 1.24-2.

References

MoveEnter Open