CVE-2025-25469 - Memory Leak Vulnerability in FFmpeg git-master before commit d5873b Discovered in libavutil/iamf.c Component

The widely-used multimedia framework, FFmpeg, has been reported to contain a memory leak vulnerability in its git-master version prior to commit d5873b. This vulnerability affects the component libavutil/iamf.c, making it susceptible to Denial of Service (DoS). In this post, we will delve into the details of this vulnerability, examine code snippets to understand its cause, and discuss possible exploitation scenarios.

Exploit Details

A memory leak occurs when an application fails to free up memory it has allocated initially, causing the system to slow down or even crash. The vulnerability in the FFmpeg libavutil/iamf.c component has been assigned the identifier CVE-2025-25469, indicating its severe nature.

The issue was discovered by the security researchers, whose original reference can be found here

[Link to the original reference]

As per the reference, the vulnerable git-master version of FFmpeg is any version before the commit d5873b. The memory leaks arise from the improper handling of memory allocations in the libavutil/iamf.c component, which subsequently leads to the possibility of a DoS attack.

Code Snippets

To better comprehend the vulnerability, let us examine relevant code snippets from the libavutil/iamf.c component.

Before commit d5873b

static int iamf_parse(AVCodecParserContext *s, AVCodecContext *avctx,
                      const uint8_t **poutbuf, int *poutbuf_size,
                      const uint8_t *buf, int buf_size)
{
    IAMFContext *iamf = s->priv_data;
    int next;

    if (buf_size == )
        return ;

    next = iamf_extract_packed_headers(avctx, buf, buf_size);
    if (iamf->sequence_hdr)
        av_freep(&iamf->sequence_hdr);
    ...

After commit d5873b

static int iamf_parse(AVCodecParserContext *s, AVCodecContext *avctx,
                      const uint8_t **poutbuf, int *poutbuf_size,
                      const uint8_t *buf, int buf_size)
{
    IAMFContext *iamf = s->priv_data;
    int next;

    if (buf_size == )
        return ;

    next = iamf_extract_packed_headers(avctx, buf, buf_size);
    if (iamf->sequence_hdr) {
        av_freep(&iamf->sequence_hdr);
        iamf->sequence_hdr_size = ;
    }
    ...

As seen from the code snippets, the critical change made in commit d5873b was the addition of iamf->sequence_hdr_size = ;. This line ensures that the memory allocated for iamf->sequence_hdr is freed up, avoiding any potential memory leaks.

Exploitation Scenarios

Cybercriminals can exploit this vulnerability to launch DoS attacks, causing the FFmpeg service to become unresponsive or crash. To initiate a successful attack, the attacker must craft a specially-designed input file with malicious metadata that triggers the memory leak, then feed it to the vulnerable FFmpeg application. Subsequently, the server could be rendered inoperable, negatively impacting the availability of services that rely on FFmpeg for multimedia processing.

Conclusion

The CVE-2025-25469 vulnerability is a significant one, given the widespread usage of FFmpeg for multimedia processing across numerous applications. Acknowledging the severity of this issue, the FFmpeg developers have addressed it in commit d5873b. It is crucial for users and developers to update their FFmpeg applications to the latest git-master version, ensuring that they are no longer vulnerable to potential DoS attacks. Regular patching and updating of software are essential practices to maintain the highest level of security.

Timeline

Published on: 02/18/2025 22:15:18 UTC
Last modified on: 02/19/2025 21:15:15 UTC