# CVE-2023-5363: Incorrect cipher key & IV length processing

> Incorrect key and IV length processing in OpenSSL can cause IV truncation, leading to potential loss of confidentiality in specific cipher modes.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Oct 2023
- **Updated:** 14 Oct 2026
- **Also known as:** ALPINE-CVE-2023-5363, ALSA-2024:0310, AZL-42712, AZL-42751, AZL-78558, BELL-CVE-2023-5363, CLEANSTART-2026-KN91701, CLSA-2023-1702495193, CLSA-2024-1709548308, DEBIAN-CVE-2023-5363, DSA-5532-1, GHSA-xw78-pcr6-wrg8, JLSEC-2026-243, MGASA-2023-0313, MGASA-2023-0317, RHSA-2024:0310, RHSA-2024:0500, UBUNTU-CVE-2023-5363, openSUSE-SU-2024:13372-1

## What is CVE-2023-5363?

CVE-2023-5363 is a high-severity vulnerability in Debian Debian Linux, published on 24 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Issue summary: A bug has been identified in the processing of key and
initialisation vector (IV) lengths.  This can lead to potential truncation
or overruns during the initialisation of some symmetric ciphers.

Impact summary: A truncation in the IV can result in non-uniqueness,
which could result in loss of confidentiality for some cipher modes.

When calling EVP_EncryptInit_ex2(), EVP_DecryptInit_ex2() or
EVP_CipherInit_ex2() the provided OSSL_PARAM array is processed after
the key and IV have been established.  Any alterations to the key length,
via the "keylen" parameter or the IV length, via the "ivlen" parameter,
within the OSSL_PARAM array will not take effect as intended, potentially
causing truncation or overreading of these values.  The following ciphers
and cipher modes are impacted: RC2, RC4, RC5, CCM, GCM and OCB.

For the CCM, GCM and OCB cipher modes, truncation of the IV can result in
loss of confidentiality.  For example, when following NIST's SP 800-38D
section 8.2.1 guidance for constructing a deterministic IV for AES in
GCM mode, truncation of the counter portion could lead to IV reuse.

Both truncations and overruns of the key and overruns of the IV will
produce incorrect results and could, in some cases, trigger a memory
exception.  However, these issues are not currently assessed as security
critical.

Changing the key and/or IV lengths is not considered to be a common operation
and the vulnerable API was recently introduced. Furthermore it is likely that
application developers will have spotted this problem during testing since
decryption would fail unless both peers in the communication were similarly
vulnerable. For these reasons we expect the probability of an application being
vulnerable to this to be quite low. However if an application is vulnerable then
this issue is considered very serious. For these reasons we have assessed this
issue as Moderate severity overall.

The OpenSSL SSL/TLS implementation is not affected by this issue.

The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this because
the issue lies outside of the FIPS provider boundary.

OpenSSL 3.1 and 3.0 are vulnerable to this issue.

Weakness: CWE-684 (Incorrect Provision of Specified Functionality)

## Which versions are affected by CVE-2023-5363?

It affects 7 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `openssl` | AlmaLinux:9 | All versions | 1:3.0.7-25.el9_3 |
| `openssl-devel` | AlmaLinux:9 | All versions | 1:3.0.7-25.el9_3 |
| `openssl-libs` | AlmaLinux:9 | All versions | 1:3.0.7-25.el9_3 |
| `openssl-perl` | AlmaLinux:9 | All versions | 1:3.0.7-25.el9_3 |
| `openssl-debuginfo` | Red Hat:enterprise_linux:9::appstream | All versions | 1:3.0.7-25.el9_3 |
| `openssl-debugsource` | Red Hat:enterprise_linux:9::appstream | All versions | 1:3.0.7-25.el9_3 |
| `openssl-devel` | Red Hat:enterprise_linux:9::appstream | All versions | 1:3.0.7-25.el9_3 |
| `openssl-libs-debuginfo` | Red Hat:enterprise_linux:9::appstream | All versions | 1:3.0.7-25.el9_3 |
| `openssl-perl` | Red Hat:enterprise_linux:9::appstream | All versions | 1:3.0.7-25.el9_3 |
| `openssl` | Red Hat:enterprise_linux:9::baseos | All versions | 1:3.0.7-25.el9_3 |
| `openssl-debuginfo` | Red Hat:enterprise_linux:9::baseos | All versions | 1:3.0.7-25.el9_3 |
| `openssl-debugsource` | Red Hat:enterprise_linux:9::baseos | All versions | 1:3.0.7-25.el9_3 |
| `openssl-libs` | Red Hat:enterprise_linux:9::baseos | All versions | 1:3.0.7-25.el9_3 |
| `openssl-libs-debuginfo` | Red Hat:enterprise_linux:9::baseos | All versions | 1:3.0.7-25.el9_3 |
| `openssl-debuginfo` | Red Hat:rhel_eus:9.2::appstream | All versions | 1:3.0.7-18.el9_2 |
| `openssl-debugsource` | Red Hat:rhel_eus:9.2::appstream | All versions | 1:3.0.7-18.el9_2 |
| `openssl-devel` | Red Hat:rhel_eus:9.2::appstream | All versions | 1:3.0.7-18.el9_2 |
| `openssl-libs-debuginfo` | Red Hat:rhel_eus:9.2::appstream | All versions | 1:3.0.7-18.el9_2 |
| `openssl-perl` | Red Hat:rhel_eus:9.2::appstream | All versions | 1:3.0.7-18.el9_2 |
| `openssl` | Red Hat:rhel_eus:9.2::baseos | All versions | 1:3.0.7-18.el9_2 |
| `openssl-debuginfo` | Red Hat:rhel_eus:9.2::baseos | All versions | 1:3.0.7-18.el9_2 |
| `openssl-debugsource` | Red Hat:rhel_eus:9.2::baseos | All versions | 1:3.0.7-18.el9_2 |
| `openssl-libs` | Red Hat:rhel_eus:9.2::baseos | All versions | 1:3.0.7-18.el9_2 |
| `openssl-libs-debuginfo` | Red Hat:rhel_eus:9.2::baseos | All versions | 1:3.0.7-18.el9_2 |
| `openssl-3` | openSUSE:Tumbleweed | All versions | 3.1.4-1.1 |

Products: Debian Debian Linux, Netapp H300s Firmware, Netapp H410c Firmware, Netapp H410s Firmware, Netapp H500s Firmware, Netapp H700s Firmware, Openssl Openssl.

## How do I fix CVE-2023-5363?

Apply the vendor's patch.

## Is CVE-2023-5363 being exploited?

There is no known exploitation of CVE-2023-5363 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
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- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-5363 and fix it if it is affected.

What it is: CVE-2023-5363 is a high-severity vulnerability in Debian Debian Linux, published on 24 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-5363 in the wild and no public exploit code.

Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-5363/ (Markdown: https://insights.sbomify.com/CVE-2023-5363/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-5363
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-5363
- OSV: https://osv.dev/vulnerability/CVE-2023-5363

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-5363/
Summaries are generated and may contain mistakes; the official description above is the record.