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CVE-2026-53585

libgit2: Unbounded Memory Allocation via Delta Object Result-Size Header

5.3 MediumFix available

libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, git_delta_apply in src/libgit2/delta.c trusts the attacker-controlled res_sz value parsed by hdr_sz from a delta object header and passes that amount to git__malloc before validating delta instructions. Malicious pack data supplied through git_clone, git_fetch, git_remote_fetch, git_indexer_append, or a local attacker-supplied repository can use a very small multi-level OFS_DELTA chain to retain extremely large allocations and exhaust memory. This issue is fixed in versions 1.8.6 and 1.9.5.

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
None
Integrity
None
Availability
Low

Exploit likelihood

0.40%Down 0.2 points since Aug 21, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.3

libgit2: Unbounded Memory Allocation via Delta Object Result-Size Header

libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, git_delta_apply in src/libgit2/delta.c trusts the attacker-controlled res_sz value parsed by hdr_sz from a delta object header and passes that amount to git__malloc before validating delta instructions. Malicious pack data supplied through git_clone, git_fetch, git_remote_fetch, git_indexer_append, or a local attacker-supplied repository can use a very small multi-level OFS_DELTA chain to retain extremely large allocations and exhaust memory. This issue is fixed in versions 1.8.6 and 1.9.5.

Record
CVE-2026-53585
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-770
Updated
2026-11-02
EUVDEUVD-2026-63548 5.3

libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, git_delta_apply in src/libgit2/delta.c trusts the attacker-controlled res_sz value parsed by hdr_sz from a delta object header and passes that amount to git__malloc before validating delta instructions. Malicious pack data supplied through git_clone, git_fetch, git_remote_fetch, git_indexer_append, or a local attacker-supplied repository can use a very small multi-level OFS_DELTA chain to retain extremely large allocations and exhaust memory. This issue is fixed in versions 1.8.6 and 1.9.5.

Record
EUVD-2026-63548
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
NVD 5.3

libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, git_delta_apply in src/libgit2/delta.c trusts the attacker-controlled res_sz value parsed by hdr_sz from a delta object header and passes that amount to git__malloc before validating delta instructions. Malicious pack data supplied through git_clone, git_fetch, git_remote_fetch, git_indexer_append, or a local attacker-supplied repository can use a very small multi-level OFS_DELTA chain to retain extremely large allocations and exhaust memory. This issue is fixed in versions 1.8.6 and 1.9.5.

Record
CVE-2026-53585
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-770
Updated
2026-11-02
OSVALPINE-CVE-2026-53585 5.3

libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, git_delta_apply in src/libgit2/delta.c trusts the attacker-controlled res_sz value parsed by hdr_sz from a delta object header and passes that amount to git__malloc before validating delta instructions. Malicious pack data supplied through git_clone, git_fetch, git_remote_fetch, git_indexer_append, or a local attacker-supplied repository can use a very small multi-level OFS_DELTA chain to retain extremely large allocations and exhaust memory. This issue is fixed in versions 1.8.6 and 1.9.5.

Record
ALPINE-CVE-2026-53585
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-03
OSVBELL-CVE-2026-53585 5.3
Record
BELL-CVE-2026-53585
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSV 5.3

libgit2: Unbounded Memory Allocation via Delta Object Result-Size Header

libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, git_delta_apply in src/libgit2/delta.c trusts the attacker-controlled res_sz value parsed by hdr_sz from a delta object header and passes that amount to git__malloc before validating delta instructions. Malicious pack data supplied through git_clone, git_fetch, git_remote_fetch, git_indexer_append, or a local attacker-supplied repository can use a very small multi-level OFS_DELTA chain to retain extremely large allocations and exhaust memory. This issue is fixed in versions 1.8.6 and 1.9.5.

Record
CVE-2026-53585
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-770
Updated
2026-11-02
Show 7 moreShow less
OSVDEBIAN-CVE-2026-53585 5.3

libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, git_delta_apply in src/libgit2/delta.c trusts the attacker-controlled res_sz value parsed by hdr_sz from a delta object header and passes that amount to git__malloc before validating delta instructions. Malicious pack data supplied through git_clone, git_fetch, git_remote_fetch, git_indexer_append, or a local attacker-supplied repository can use a very small multi-level OFS_DELTA chain to retain extremely large allocations and exhaust memory. This issue is fixed in versions 1.8.6 and 1.9.5.

Record
DEBIAN-CVE-2026-53585
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVJLSEC-2026-1371 5.3

libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, git_delta_apply in src/libgit2/delta.c trusts the attacker-controlled res_sz value parsed by hdr_sz from a delta object header and passes that amount to git__malloc before validating delta instructions. Malicious pack data supplied through git_clone, git_fetch, git_remote_fetch, git_indexer_append, or a local attacker-supplied repository can use a very small multi-level OFS_DELTA chain to retain extremely large allocations and exhaust memory. This issue is fixed in versions 1.8.6 and 1.9.5.

Record
JLSEC-2026-1371
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVRHSA-2026:59361 7.5

Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update

Record
RHSA-2026:59361
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2026-53585 5.3

libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, git_delta_apply in src/libgit2/delta.c trusts the attacker-controlled res_sz value parsed by hdr_sz from a delta object header and passes that amount to git__malloc before validating delta instructions. Malicious pack data supplied through git_clone, git_fetch, git_remote_fetch, git_indexer_append, or a local attacker-supplied repository can use a very small multi-level OFS_DELTA chain to retain extremely large allocations and exhaust memory. This issue is fixed in versions 1.8.6 and 1.9.5.

Record
UBUNTU-CVE-2026-53585
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVAZL-96965 No score

CVE-2026-53585 affecting package libgit2 for versions less than 1.7.2-3

libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, git_delta_apply in src/libgit2/delta.c trusts the attacker-controlled res_sz value parsed by hdr_sz from a delta object header and passes that amount to git__malloc before validating delta instructions. Malicious pack data supplied through git_clone, git_fetch, git_remote_fetch, git_indexer_append, or a local attacker-supplied repository can use a very small multi-level OFS_DELTA chain to retain extremely large allocations and exhaust memory. This issue is fixed in versions 1.8.6 and 1.9.5.

Record
AZL-96965
Updated
2026-11-05
OSVMGASA-2026-0570 No score

Updated libgit2 package fixes security vulnerabilities

Inverted IP SubjectAltName Comparison in OpenSSL Backend. (CVE-2026-53583) Submodule path traversal. (CVE-2026-53584) Unbounded Memory Allocation via Delta Object Result-Size Header. (CVE-2026-53585) HTTP transport can leak credentials to an offsite redirect target. (CVE-2026-53586) Unauthenticated network-reachable heap out-of-bounds read in transports/smart_pkt.c:set_data. (CVE-2026-53587) Shell Command Injection via ssh_libssh2 Backend. (CVE-2026-5917)

Record
MGASA-2026-0570
Updated
2026-11-02
OSVopenSUSE-SU-2026:11315-1 No score

libgit2-1_9-1.9.6-1.1 on GA media

These are all security issues fixed in the libgit2-1_9-1.9.6-1.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:11315-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
libgit2
Alpine:v3.23
before 1.9.6-r0
1.9.6-r0
libgit2
Alpine:v3.24
before 1.9.6-r0
1.9.6-r0
libgit2
Azure Linux:3
before 1.7.2-3
1.7.2-3
libgit2
Alpaquita:25
1.9.0-r2 up to 1.9.6-r0
1.9.6-r0
libgit2
Alpaquita:stream
1.7.1-r0 up to 1.9.6-r0
1.9.6-r0
libgit2
Debian:12
before 1.5.1+ds-1+deb12u2, plus listed versions
1.5.1+ds-11.5.1+ds-1+deb12u1
1.5.1+ds-1+deb12u2
libgit2
Debian:13
before 1.9.0+ds-2+deb13u1, plus listed versions
1.9.0+ds-2
1.9.0+ds-2+deb13u1
libgit2
Debian:14
before 1.9.6+ds-1, plus listed versions
1.9.0+ds-21.9.1+ds-11.9.2+ds-11.9.2+ds-21.9.2+ds-3
Show 8 moreShow less
1.9.2+ds-41.9.2+ds-51.9.2+ds-61.9.2+ds-71.9.2+ds-81.9.2+ds-91.9.3+ds-11.9.4+ds-1
1.9.6+ds-1
LibGit2_jll
Julia
before 1.9.6+0
1.9.6+0
libgit2
Mageia:10
From an advisory covering 6 CVEs
before 1.9.2-1.1.mga10
1.9.2-1.1.mga10
Show 10 moreShow less
Affected packages
PackageAffectedFixed
libgit2
Red Hat:hummingbird:1
From an advisory covering 5 CVEs
before 0:1.9.7-1.hum1
0:1.9.7-1.hum1
libgit2-devel
Red Hat:hummingbird:1
From an advisory covering 5 CVEs
before 0:1.9.7-1.hum1
0:1.9.7-1.hum1
libgit2
Ubuntu:Pro:14.04:LTS
before 0.19.0-2ubuntu0.4+esm2, plus listed versions
0.19.0-20.19.0-2ubuntu0.40.19.0-2ubuntu0.4+esm1
0.19.0-2ubuntu0.4+esm2
libgit2
Ubuntu:Pro:16.04:LTS
before 0.24.1-2ubuntu0.2+esm3, plus listed versions
0.22.2-20.23.1-10.24.1-20.24.1-2ubuntu0.20.24.1-2ubuntu0.2+esm10.24.1-2ubuntu0.2+esm2
0.24.1-2ubuntu0.2+esm3
libgit2
Ubuntu:Pro:18.04:LTS
before 0.26.0+dfsg.1-1.1ubuntu0.2+esm2, plus listed versions
0.25.1+really0.24.6-10.26.0+dfsg.1-1.10.26.0+dfsg.1-1.1build10.26.0+dfsg.1-1.1ubuntu0.20.26.0+dfsg.1-1.1ubuntu0.2+esm1
0.26.0+dfsg.1-1.1ubuntu0.2+esm2
libgit2
Ubuntu:Pro:20.04:LTS
before 0.28.4+dfsg.1-2ubuntu0.1+esm1, plus listed versions
0.27.7+dfsg.1-0.2build10.28.3+dfsg.1-10.28.3+dfsg.1-1ubuntu10.28.4+dfsg.1-20.28.4+dfsg.1-2ubuntu0.1
0.28.4+dfsg.1-2ubuntu0.1+esm1
libgit2
Ubuntu:Pro:22.04:LTS
before 1.1.0+dfsg.1-4.1ubuntu0.1+esm1, plus listed versions
1.1.0+dfsg.1-41.1.0+dfsg.1-4.11.1.0+dfsg.1-4.1build11.1.0+dfsg.1-4.1ubuntu0.1
1.1.0+dfsg.1-4.1ubuntu0.1+esm1
libgit2
Ubuntu:24.04:LTS
before 1.7.2+ds-1ubuntu3.1, plus listed versions
1.5.1+ds-1ubuntu11.7.1+ds-2ubuntu11.7.2+ds-1ubuntu11.7.2+ds-1ubuntu21.7.2+ds-1ubuntu3
1.7.2+ds-1ubuntu3.1
libgit2
Ubuntu:26.04:LTS
before 1.9.1+ds-1ubuntu1.1, plus listed versions
1.9.0+ds-2ubuntu21.9.1+ds-1ubuntu1
1.9.1+ds-1ubuntu1.1
libgit2
openSUSE:Tumbleweed
From an advisory covering 5 CVEs
before 1.9.6-1.1
1.9.6-1.1

History

History
RecordedChangedSources
affected
factsOSV
affected, aliases, referencesOSV
first indexedCVE List, EUVD, NVD, OSV

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

In short

CVE-2026-53585 is a medium vulnerability (CVSS 5.3) in Libgit2, published July 20, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.40%, the 33rd percentile. Fixed in libgit2 1.9.6-r0.

References

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