Circular reporting

Circular reporting, or false confirmation, is a situation in source criticism where a piece of information appears to come from multiple independent sources, but in reality comes from only one source. In many cases, the problem happens mistakenly through sloppy intelligence-gathering practices. However, at other times the situation can be intentionally contrived by the original source as a way of reinforcing the widespread belief in its information.
This problem occurs in a variety of fields, including intelligence gathering, journalism, and scholarly research. It is of particular concern in military intelligence because the original source has a higher likelihood of wanting to pass on misinformation, and because the chain of reporting is more prone to being obscured. It is also a problem in journalism and the development of conspiracy theories, in which the primary goal of a source spreading unlikely or hard-to-believe information is to make it appear to be widely known.
The case of the 2002 Niger uranium forgeries was a classic instance of circular reporting by intelligence agencies.
Circular reporting on Wikipedia.
Wikipedia is sometimes criticized for being used as a source of circular reporting, particularly a variant where an unsourced claim in a Wikipedia article is repeated by a reliable source, citing the article; which is then added as a source to the initial claim. 
History of citogenesis.
In November 2011, Randall Munroe coined the term citogenesis to describe this phenomenon in an "xkcd" comic strip, as wordplay on cytogenesis (the original process for the creation of cells) except for citations (often shortened to "cites"). The popularity of the comic brought the term into common use, and raised awareness about the risks of Wikipedia-mediated citogenesis for readers and journalists alike. 
The four-step process illustrated by the comic has been referenced as the typical way that circular reporting develops via Wikipedia. This has been described as particularly hard-to-catch because of the speed of revisions of modern webpages, and the lack of "as of" timestamps in citations and "last updated" timestamps on pages online.
Inspired by the comic, Wikipedia editors have since maintained an internal list of citogenesis incidents, to monitor its prevalence.
Wikipedia advises researchers and journalists to , and to focus instead on verifiable information found in an article's cited references. Researchers and Wikipedians alike are advised to note the retrieved-on date of any web citation, to support identification of the earliest source of a claim.
Examples on Wikipedia.
Prominent examples of false claims that were propagated on Wikipedia and in news sources because of circular reporting:
Examples outside Wikipedia.
In 2001, the Niger uranium forgeries, documents initially released by SISMI (the former military intelligence agency of Italy), seemed to depict an attempt made by Saddam Hussein in Iraq to purchase yellowcake uranium powder from Niger during the Iraq disarmament crisis. They were referenced by other intelligence agencies to convince their governments or publics that such a purchase had taken place.
In 2018, Shehroze Chaudhry was identified as an active member of the Islamic State who participated in the killing of several individuals, through reporting involving a "The New York Times" podcast, among others. The podcast and other outlets referenced blog posts authored by Chaudhry starting in 2016. The podcast was taken by government officials and others as evidence of the crime, however the original posts were unverified and later renounced by the author.