A flaw was found in libgit2 before version 0.27.3. It has been discovered that an unexpected sign extension in git_delta_apply function in delta.c file may lead to an integer overflow which in turn leads to an out of bound read, allowing to read before the base object. An attacker may use this flaw to leak memory addresses or cause a Denial of Service.
Weakness
The product performs an operation on a number that causes it to be sign extended when it is transformed into a larger data type. When the original number is negative, this can produce unexpected values that lead to resultant weaknesses.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Libgit2 | Libgit2 | * | 0.27.3 (excluding) |
| Libgit2 | Ubuntu | artful | * |
| Libgit2 | Ubuntu | bionic | * |
| Libgit2 | Ubuntu | esm-apps/bionic | * |
| Libgit2 | Ubuntu | esm-apps/xenial | * |
| Libgit2 | Ubuntu | esm-infra-legacy/trusty | * |
| Libgit2 | Ubuntu | trusty | * |
| Libgit2 | Ubuntu | trusty/esm | * |
| Libgit2 | Ubuntu | upstream | * |
| Libgit2 | Ubuntu | xenial | * |
Potential Mitigations
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1598021
- https://github.com/libgit2/libgit2/commit/3f461902dc1072acb8b7607ee65d0a0458ffac2a
- https://github.com/libgit2/libgit2/commit/c1577110467b701dcbcf9439ac225ea851b47d22
- https://github.com/libgit2/libgit2/releases/tag/v0.27.3
- https://lists.debian.org/debian-lts-announce/2018/08/msg00024.html
- https://lists.debian.org/debian-lts-announce/2022/03/msg00031.html
- https://bugzilla.redhat.com/show_bug.cgi?id=1598021
- https://github.com/libgit2/libgit2/commit/3f461902dc1072acb8b7607ee65d0a0458ffac2a
- https://github.com/libgit2/libgit2/commit/c1577110467b701dcbcf9439ac225ea851b47d22
- https://github.com/libgit2/libgit2/releases/tag/v0.27.3
- https://lists.debian.org/debian-lts-announce/2018/08/msg00024.html
- https://lists.debian.org/debian-lts-announce/2022/03/msg00031.html